System Features
Not all methods of heating a private house include a water pipeline, although it is the most popular. Another option is air heating. This includes gas and electric convectors, all other electrical appliances, except for an electric boiler - it works with liquid heat carriers.
In the solid fuel category, this is a Buleryan boiler - it heats the room according to the principle of convection through pipes extending from the furnace. With a large area of \u200b\u200bthe house, air ducts are connected to the nozzles.
Scheme of the device of the boiler "Buleryan".
If we talk about water systems, the first question is competent design. In a small one-story house, you can install a system with natural circulation, without a pump, and do without electricity at all. For a large area, this option is not suitable, heating will be uneven and inefficient.
In a large house, beam wiring outperforms others in terms of efficiency: all heaters receive a hot coolant. No need to set the initial high temperature, and this is fuel saving.
Boiler automation can be non-volatile or electronic. The second is more expensive, but more convenient and more profitable: it consumes little electricity, while allowing you to balance all the parameters as much as possible, which leads to significant savings.
Economical heating of a private house with your own hands will turn out if you install an indirect heating boiler. First of all, this applies to electric boilers, but it also applies to others: if the system works most of the time in the temperature maintenance mode, less fuel is consumed.
Heating appliances - batteries or underfloor heating. Floors - more efficient heating of a private house: due to convection, heating is high-quality and uniform. In addition, the temperature near the floor is on average 40 degrees lower than that of the batteries. In addition to water floors, there are electric ones. Often this is the most economical heating of a private house with electricity.
Finally, the thermal insulation of the house must be of high quality over the entire surface: walls, roof, attic, basement, window and door openings. This reduces natural heat loss, and hence costs.
How to heat a house cheaply without gas and electricity
April 06, 2016, 18:34 Debugger Slava 15500 1
How to heat the house if there is no gas? How do solid fuel boilers work and how much do they cost? How to heat the house with the energy of the sun and heat pumps? How to use biofuel and how is it profitable to heat brick ovens?
The evolution of comfort resources is rapidly evolving. However, it does not exclude traditional methods of heating. Nowadays, infrared heating of a home can successfully coexist with a classic brick stove designed for firewood and coal.
Certainly. using gas and electricity for heating is convenient, although it can be somewhat costly. And it's not just about the price of energy resources. Often, the allocated power does not allow for the heating system at home. For example, if there is no connection to the main gas pipeline, it will not be cost-effective to use gas in cylinders for heating. Expensive and annoying.
I have already written about how cheaply, but effectively, to heat a house with electricity. Today I will tell you how to heat the house if there is no gas and electricity.
Liquefied gas
Liquefied gas is transported and stored in cylinders or in gas tanks specially designed for this purpose.
In order to heat a country house, you can purchase cylinders with liquefied gas. Its basis is propane-butane composition. Heating a country house with liquefied gas is much more expensive than natural gas, but often cheaper than diesel fuel and electricity.The cost is reduced if a large capacity storage with appropriate equipment is installed for several houses.
There are no fundamental differences in the design of heat generating equipment for natural and liquefied gas: conventional boilers are used, the only difference is in the adjustment: the pressure in the gas pipeline is lower. In some cases, it will be necessary to replace the jets in the burners, it is inexpensive and the equipment can be quickly returned to its original condition.
A gas tank is a container used to store liquefied gas in large quantities. Such tanks are installed both on the surface of the earth and underground. Most often, for country houses, an underground option for installing a gas tank is chosen in order to save space and money. The depth of its occurrence must necessarily be not lower than the freezing level of the soil.
In the countries of Western Europe, gas storage systems are used quite widely; in our country, the service of liquefied gas delivery is underdeveloped and not available everywhere. For small houses, groups of standard liquefied gas cylinders can also be used. True, their capacity is too small to ensure the operation of the boiler for a long time, frequent replacement, taking into account transportation costs, can make the operation of the system on cylinders more expensive than heating with diesel fuel. For a small dacha, we can recommend the use of bottled gas with a convector. But only with strict observance of fire safety measures!
Convectors and warm plinth
The convector is also not the cheapest model, since everything depends on electricity, and energy prices are quite high.
Recently, the warm baseboard system has proven itself well, which replaced stationary radiators and works on the principle of heating a liquid coolant, which creates a thermal screen around the perimeter of all rooms. This is practically the most economical home heating, which also has a beneficial effect on health, prevents the appearance of dampness and condensate, and also creates heating savings.
Thanks for the info. Helpful, informative. I will definitely refuse oil.
Good afternoon Oleg. Rarely do you get such constructive feedback. It is immediately clear that you actually studied this issue for a long time and painfully. After reading everything to the end, I want to share my experience with you. Just like you came to exactly the same heating scheme. BUT. Having sat down and considered the benefit of the nightly tariff for electricity, and the fact that we are mainly at work during the day and turn off the heating, I decided that I would order a 3m3 heat accumulator. Yes, it will take some place, but the coolant, if not water, will not be cheap. But after considering the effect of such an undertaking, I came to the conclusion that this is the very thing. I will not describe the principle of operation, you will understand everything yourself.
Heating systems used in modern conditions
The refusal to use electric heating systems is obvious, because this is the most expensive form of energy. The efficiency of electric heaters remains low at high power consumption, and heat losses in private houses are always higher than in multi-apartment houses. In addition to these conditions, it is necessary to take into account the need for a special boiler room, its and other problems.
Stove heating
For obvious historical reasons, the most popular method of space heating is stove. The classic version assumes that a stone stove installed in a specially designated place heats a room or a group of rooms. The heat source in this case is the burning solid fuel, which heats the stone structure. Having a high inertia, that is, retaining heat for a long time, such a stove gradually warms the room over several hours.
The efficiency of such furnaces depends on several factors:
The construction of furnaces is a complex technological process, amateurs cannot do it, so it is imperative to involve an experienced craftsman, at least as a consultant.
Water heating with the construction of a furnace
The stove can be an independent source of heat, but it can also serve as a heater in a water heating system. In large houses or two-story cottages, this option is not possible without the use of a water pump, which is powered by electricity and drives water through the system. If the length of the pipes is small, and the radiators have a pipe cross section of 32 mm or more, then it is possible to arrange without gas and electricity with natural circulation.
The principle of operation of such a heating system is known to many rural residents. Inside the furnace, in a zone close to the burning fuel, a collector welded from thick-walled metal pipes is mounted, in which water is heated. According to the law of physics, hot water rises up through a specially equipped pipe. Then it enters the heating pipeline, which is located with a slight slope, which is maintained throughout its entire length. According to the same physical laws, the liquid flows downwards, passes through the entire system, gives off heat, eventually falling back into the collector inside the furnace, where the circle is renewed.
The installation of such a system requires an accurate calculation of the angle of inclination of the pipes, the presence of an expansion tank. The temperature of such heating can be regulated using valves that reduce the amount of hot water supplied to the system. In some cases, it is possible to install two or more heating circuits.
Fireplace heating
Fireplaces are more of a stylish addition to an interior than an effective source of heat. In order for the fireplace to heat at least a room, it is necessary to make serious changes to its design and turn it into a classic stove that only looks like a fireplace. In such a pseudo-fireplace, a shelf is kept, and the flame is closed with a refractory glass door.
Alternative sources
Heating a private wooden house without gas and electricity using exotic sources such as solar panels and geothermal heat is of great interest to advanced owners. In both cases, certain climatic conditions are required. Geothermal sources are found in a very small number of places on the planet, usually they are present in seismically active zones. For residents of 99% of the territory of Russia, this type of heating is not available.
Solar panels are mounted on the roof, as they need a large area to work efficiently. It is known that snow falls in winter, which will have to be cleaned several times a day. In addition, in many regions in winter, the daylight hours are so short that it is simply impossible to accumulate the necessary charge.
Device and operation
The heat pump consists of tubes that are filled with freon, as well as several chambers, namely a heat exchanger, a throttle chamber and a compressor. This device will work by analogy with a refrigerator. The principle of operation in this case is based on liquid freon, which passes through tubes lowered into the ground or a reservoir. There, in winter, the temperature does not fall below plus 8 degrees. Freon under such conditions begins to boil, for this it needs only 3 degrees of heat.
Rising up, the substance, which becomes gaseous, enters the compressor chamber, where it is significantly compressed. As you know, if you compress any substance in a limited space, this leads to an increase in its temperature, so freon heats up to 80 degrees.
Giving off the generated heat through the heat exchanger of the heating system, the mass passes into the throttle chamber, where the temperature and pressure decrease, thereby freon turns into a liquid. At the next stage, he goes into the depths to warm up and repeat the cycle again.
Still not sure how cheap it is to heat a house without gas? You can apply this rather effective technology, for the implementation of which, of course, you will need electricity. However, it will be consumed in a disproportionately smaller amount compared to direct heating of the coolant.
Solar collectors
An excellent alternative to gas heating is solar collectors. Such installations operate smoothly and economically. Collectors are ways to keep the heat in the room for a long time. But the main thing is that under good conditions they can generate electricity. Such installations have both advantages and disadvantages.
So, solar collectors are absolutely safe. Mounting such installations is quite simple and fast. Collectors are installed in any place on the facade of the building. The installation will perfectly fit into the design of the house, since among the wide range you can choose the most suitable option for yourself. But most importantly, collectors provide significant savings in utility costs. Therefore, this type of installation is perfect even for low-income families.
The only drawback of such collectors is that they are powered solely by solar energy. This predetermines the specifics of the installation of collectors. In regions where it is sunny almost all year round (usually the south of the country), the installation of collectors is fully justified. But in the northern latitudes, these installations will be completely useless.
Classic oven heating
In certain cases, a stove is the only possible way to organize heat in a house.
Stove heating is considered the oldest. Stove heating is still often used in suburban buildings. Do not think that this method is outdated. The lack of gas in some regions makes this type of heating still very popular and in demand. Combined stoves remain in fashion, allowing you to both heat the room and cook food. Among the advantages of this option can be noted savings in installation, operation, and fuel, multifunctionality. With all this, the furnaces need to be heated several times a day, they require constant maintenance. In addition, the risk of fire is high, the stoves are quite large and take up a lot of space. The room in which the stove is installed is always polluted with soot and coal, and will also require constant cleaning and regular maintenance. There is a high risk of carbon monoxide poisoning if the furnace is not used correctly.
Oil boilers efficiently and reliably
In terms of performance and characteristics, liquid fuel boilers are very close to gas boilers, a significant difference is only in the cost and type of fuel that they use: fuel oil, diesel fuel (diesel fuel or kerosene), less often rapeseed oil. Here are their most important features:
- Difficulties often arise during the delivery and storage of fuel, which is characterized by high cost and flammability.
- When using these boilers, there is a need for an additional room - a boiler room.
- Diesel boilers "bypassed" all the others in terms of the emission of harmful substances into the atmosphere, in addition, they need high-quality protective automation.
- Liquid fuel boilers have an excellent efficiency index.
With a power of up to 10 kW, for example, they can easily heat a house up to 100 m2, so they are suitable even for large buildings. There are hot water and steam boilers, most of them are compact and easy to install.
Solid fuel boilers
Now people have a great alternative, they do not have to build a stove if they want to give up gas or electricity heating. Modern solid fuel boilers allow you to heat the house with wood, coal or pallets.They are designed so that the coolant in them is heated to a predetermined temperature, and then enters the radiators designed to heat the house.
There are also generic options. For example, a gas-firewood heating boiler can fully operate both on solid fuel and on gas. Such options are initially equipped with two combustion chambers. Depending on the chosen model, a gas burner can be installed in them, but in some cases it is necessary to buy it yourself.
Also on sale you can find combined gas-firewood-electricity heating boilers. In addition to fireboxes designed for the use of solid fuel or gas, they are additionally equipped with heating elements. Depending on the situation, the owner of such a unit can choose its mode of operation and change the energy source at its discretion. There are models that change the type of fuel automatically. For example, you can fill up firewood at night, and when they burn out, the boiler will automatically switch to gas heating.
But the cost of universal models is quite high. The average option will cost 200-300 thousand rubles. They are usually used year-round, because these double-circuit boilers not only heat the premises, but also heat the water.
solar heating
You can convert solar energy into thermal energy only if the sun shines often and for a long time over the roof of your house. Unfortunately, 80% of the territories of Russia have nothing to do with this. However, even in a warm climate, you cannot rely on solar heating alone; you definitely need a backup source.
Principle of operation
Light-absorbing batteries are installed in place "under the sun", which convert solar energy immediately into heat, and then transfer it to the coolant. There are two kinds solar collectors - vacuum and flat. Vacuum are considered the most efficient and economical. The use of solar energy is an achievement of science.
Choice of energy carrier
There is an inverse relationship between the efficiency of heating and the cost of equipment: the more expensive the purchase, the cheaper the operation will be.
What is the most economical heating in a private house - there is no universal answer to this question.
In forests, the cheapest fuel can be firewood, in areas of coal or peat mining - respectively, coal or peat.
Somewhere there is an opportunity to connect gas, but somewhere it is not. The most economical electric heating is expensive anyway, but there are options to choose from. For heating houses are used:
- gas boilers and convectors;
- solid fuel - firewood, pellets, coal, peat, briquettes, woodworking and crop production waste;
- liquid fuel;
- electric boilers. other electrical appliances;
- heat pumps. We will not consider this option: installation of the system is very expensive, pays off from 10 years;
- solar panels and collectors. Installation is not justified: batteries collect little energy on winter and cloudy days.
The purchase of a diesel boiler is justified when the economy is large (for example, a farm), and the owners have access to cheap fuel. Diesel boilers are produced only with high power; for a medium-sized house, these are not required.
And the equipment has many shortcomings: environmental damage, noisy operation, large dimensions and weight, fire hazard. Environmentally harmful and fire hazardous is also a compact modification of the liquid-fuel unit - a mining boiler. It is low-power, but they don’t put it in the house, only in utility buildings.
Another option is how to save on heating a private house: purchase a combined / universal boiler for two or more types of fuel. When buying it will cost more than any other.
But, firstly, under no circumstances will you be left without heating: in the absence of one energy carrier, you will switch to another. Secondly, there is room for savings.For example, expensive electricity can be burned only at “cheap” night time (with two-tariff payment), and during the day it can be heated with wood or coal.
Work organization
To install a heat pump, you need to make a circuit. If your house is on rocky soil, then one or more wells are made in it. Their total length is calculated based on the fact that for every meter of recess in the ground there is about 50 W of energy. If you plan to install a 10 kW heat pump, then you will need wells with a total depth of about 200 m.
If there is a plot of about 600 m 2 near your house, then you can make an earthen contour. In order to make heating without gas and firewood, it is necessary to install special pipelines at the depth of soil freezing. To obtain 10 kW, it is necessary that the circuit be about 500 m long.
The most preferred option is to use the nearest body of water. It must be flowing and large enough in size. It is necessary to install a water circuit in it, with a total length of 333 m. This length is sufficient to produce 10 kW.
Air circuits are rarely used. This is due to the fact that the minimum temperature at which such a pump can operate is -20 o C.
The principle of its operation is the same as that of any refrigeration machine. It consumes electricity and converts it into heat energy. The pump removes heat from the cooled products, and the condenser transfers it to the room. That is, heat is taken from the bowels of the earth.
Why electricity
Electric heating differs from classic water-furnace and gas systems in greater efficiency and practicality. We will leave the first aspect for discussion a little lower, and describe the operational advantages here:
Electric heating is not only silent, but also environmentally friendly. It is transported safer than gas and does not emit harmful substances at all, both into the atmosphere and into the premises. In the absence of waste, the need for exhaust chimneys and traction structures also disappears. Heating on coal or wood is not at all comparable to electrical systems.
Heating with electricity does not require large one-time costs. You can make a comparison using the example of gas: in order to connect a house, you must purchase equipment for each room, install communications, a boiler, and crash into a common highway. Moreover, it is necessary to do all this together, since it is impossible to postpone bringing some part of the house to the system. And the electric method allows you to organize sequential installation: first, the most important parts of the house are connected, and then, as funds accumulate, peripheral ones.
Due to the possibility of using a multi-tariff meter in a private house or apartment, as well as the constant development of technologies in this area, heating with electricity is already the most economical among analogues
Do not focus on the high price of equipment - it quickly pays off due to low energy consumption.
Almost every method of organizing electric heating allows you to do the installation yourself, without many additional tools.
Of course, the use of electrical systems for heating cannot be called ideal. Work on high-quality heating of each house requires taking into account many features. In some regions, the cost of electricity can be so high that gas cannot be abandoned. In old apartment buildings, it is difficult to switch to electric heating for two reasons: it is very difficult to disconnect from the central highway, and the power grid will have to be built again, taking into account powerful equipment.
Despite this, the overall picture tips the scales in favor of electricity. For rooms in which there is no gas or there is no possibility of supplying it, it is a real salvation.
Electricity is a worthy replacement for gas due to its absence
Economical, efficient heating of a private house, dacha without gas should be more focused on maintaining familiar living conditions. The level of comfort determines the choice of an alternative method of heating, in addition, today technology provides ample opportunities for maneuver. To achieve gas savings in the cold season will allow the availability of electricity. It is not for nothing that many owners of country houses and country cottages, due to the lack of technical possibilities for connecting to a gas main, prefer electric heating systems.
Compared to other heating devices, electric heaters have almost 100% efficiency. A boiler powered by electricity is easy to maintain, inexpensive. In this case, the need for exhaust and chimney equipment is eliminated
Electricity is by far the most affordable alternative to gas heating in terms of efficiency and serviceability.
In addition to installing an electric boiler for a water heating system in a house, convectors, heat guns and infrared emitters are actively used to heat residential buildings of a small area. A fashionable phenomenon today is the equipment of underfloor heating in a private house. The technology is quite new, however, has already managed to prove its effectiveness. A variety of offered heat sources give you the opportunity to choose the best way to heat your home.
In the event that a warm floor is the main source of heating for residential premises for you, the power of the equipment should be 150-180 W per m 2 of living space. Warm floors should have an area of at least 70-80% of the total area of the building itself. Otherwise, the expected heating effect will be negligible.
When heating a private house in other ways, even higher economic indicators can be achieved. Without gas, an economical and uninterrupted source of thermal energy on your site can be obtained using a heat pump. The principle of operation of the equipment is based on the temperature difference, in the depth of the soil and on the surface. With the help of a heat pump, which really costs a lot of money, you can provide yourself with an almost eternal source of heat in a country house. The effectiveness of this system is confirmed by simple calculations. An indicator of the successful operation of a heat pump is the heat conversion coefficient (COP).
For example. When the heat pump consumes 1 kW of electricity required to ensure the operation of the entire system (Ptn), the heat conversion coefficient (COP) is 3.0, which means:
Ртн x СОР = 3 kW Рp of energy at the output. Savings and efficiency of this method of heating is more than obvious.
There is no single answer to the question of whether it is more profitable to heat a private house with gas or other types of fuel. In each individual case, the presence of a variety of factors plays a role, among which the economic and technical capabilities of the consumer occupy not the last place.
Almost any fuel can be used instead of gas for heating. Another thing is how much you can fully heat your own house in cold weather, create comfortable living conditions for yourself. Faced with this situation, the choice is yours. How to save, make your heating costs optimal depends on you, on your attitude to the very fact of energy savings and technical capabilities.
- Do-it-yourself project and calculation of a brick fireplace
- How to lay and insulate heating pipes in the ground?
- Why do you need a plinth for heating pipes?
- Choosing ribbed registers, radiators and heating pipes
- How to hide a heating pipe?
Solid fuel boilers and furnaces
How to heat a house cheaply? The most affordable and initially cheap option for heating a country house today is the use of ordinary firewood. It is an old and proven safe fuel. But if in a simple village small house people have enough firewood and a small stove, then this will not be enough for a modern country house. And here special boilers that run on solid fuel will come to the rescue.
As a rule, firewood gives a large amount of heat. Therefore, with the help of them, you can also heat the room, cook food and heat water if necessary. If we are talking about heating a large house with several rooms, then one boiler or stove will not be enough. Here, special batteries or radiators will come to the rescue, which will distribute heat to all rooms from the main source installed in a certain place. Heat will circulate throughout the heating system. If desired, such a system can be made adjustable, which will allow you to heat some rooms and leave others cold.
To date, there are 3 main types of solid fuel boilers. These are pyrolysis units, classic devices and gas-generating boilers. Each model has both its undeniable advantages and disadvantages. Classical installations are considered the most inexpensive and in demand. They are not so expensive, they work almost smoothly and without serious breakdowns.
But still, the cheapest thing for a country house will be to acquire an ordinary wood-burning stove. Such economical heating will help solve several problems at once. It will be possible to cook food, heat water. In this case, the stove will perfectly warm the air in the room. And in regions with a particularly harsh climate, such a stove is convenient because you can also sleep on it.
Figure 1. Wood stove in a private house.
The stove can be either built in the house on your own, or you can invite a specialist who will assemble it according to a finished project. It all depends on the financial resources of the homeowner. If you approach this issue competently, then you can make such a wood-burning stove, which will not only be distinguished by high functionality, but also fit perfectly into the interior. An example of such an installation is shown in the photo (Figure 1).
But when choosing this heating option, some disadvantages should be taken into account. So, firewood will constantly have to be loaded into the oven. If coal is used, then this can be done a little less often. When using the oven, it will be necessary to strictly monitor compliance with safety rules. Another significant disadvantage for many homeowners is that when using the stove, you will need to constantly remove debris and ash. And this can only be done mechanically. Therefore, you will have to abandon the carpets in the room with the stove in advance.
How to heat a house without the use of electricity and gas, now it has become clear. What is the cheapest way to do it? Such a question cannot be answered so immediately. Here, much will depend on related factors. But still, there are many options for alternative heating. Therefore, you can always find the most suitable solution for yourself.
Solid fuel heating
The closest alternative to gas in domestic realities can be called solid fuel: firewood, peat, coal or briquettes. At a cost, solid fuel heating boilers are somewhat cheaper than gas ones, they do not require such strict control of security systems, but this is where their advantages end.
Basically, wood-burning boilers or fireplaces are seriously considered as the main way to heat a house in cases where, in the future, the slightly higher cost of fuel cannot be compared with the costs of connecting to a gas supply system over the next few decades.Such heating equipment is not without drawbacks: in the boiler it is necessary to constantly replenish the fuel tab, during combustion a significant amount of soot and ash is formed, there are difficulties with power adjustment.
We are spoiled for comfort, you can't argue with that. But after all, positive changes are also observed in the development of solid fuel heating technology, designed to increase ease of use. The simplest solution for civil residential facilities can be called long-burning boilers: they are loaded at intervals of one to several days, while the burning intensity is approximately the same both at the beginning and at the end of the cycle. Modern solid fuel boilers, equipped with automation devices, are able to maintain the temperature of the coolant with an accuracy of 2-3 ºС by regulating the air supply necessary to maintain combustion.
The most technologically advanced in this regard are heating units, purposefully designed for the use of a special type of fuel - briquettes and pellets. In the latter case, it is possible to install a bunker, as well as mechanisms for automatic fuel supply and ash removal. With such equipment, the owner of the house will have to visit the boiler room quite rarely, from 3-4 days to several weeks, it all depends on the storage capacity. Problems with the formation of soot and tar are also excluded: prepared fuel has an extremely low moisture content and does not cause moisture condensation from exhaust gases.
Metal ovens
Once they were called potbelly stoves. This name originates from the distant times of the civil war and subsequent devastation, when the simplest joys of life were associated with great wealth.
Much has changed since then, but the iron stove is still called a potbelly stove. Now they look different. Many of them are equipped with fire-resistant glass windows, but their essence has not changed - they heat up quickly and cool down just as quickly.
Maybe that's also why this stove was called a potbelly stove, because to maintain a constantly high temperature, a lot of firewood is required in a bourgeois way.
folk fantasy
In Siberian taiga huts, where it is possible to bring a cast-iron stove, but it is difficult to deliver a brick, the potbelly stove is lined on three sides with large stones, run in by the river. It turns out beautifully and functionally - the stones heat up and slowly give off heat to the air.
This technique is quite applicable in the conditions of a country house - when the house is built, and the heating is not yet ready. To some extent, the stones perform fire-fighting functions, absorbing random sparks and excessive heat. Stone structures can serve as a reason for the designer's imagination to fly.
The efficiency of a metal furnace will increase if it is equipped with a coil for heating water and heating batteries are connected to it.
conclusions
They are disappointing. A cheaper alternative to gas heating that will work in any climate is a myth. At current gas prices, it remains the most profitable source of heat. But the prospects for it, alas, are dull: gas will quickly rise in price, and the ratio of prices may still change in the direction of electricity.
Again, this is not the only point of view. Otherwise, the video at the end of the article covers this topic; you will certainly be interested in hearing another position. Warm winters!
Today, natural gas is the most popular and affordable type of fuel for domestic use and heating. However, fossil reserves are not unlimited, the cost of gas is rising, and connecting to the highway is often impossible or insanely expensive. This forces us to look for other, less familiar ways to heat housing.
