Gas consumption for heating a house of 100 m²: features of calculations for liquefied and natural gas + examples with formulas

You've probably heard more than once that gas boilers have no competitors in terms of efficiency.But, you see, healthy skepticism never hurts - as they say, trust, but verify. Therefore, before deciding to install and operate gas equipment, you should thoroughly calculate and think through everything.

We suggest that you familiarize yourself with the calculation steps and formulas that determine the gas consumption for heating a house of 100 m² taking into account all significant factors. After reviewing the calculations, you will be able to draw your own conclusion about how profitable it is to use blue fuel as a source of thermal energy.

Formulas for heat load and gas flow

Gas consumption is conventionally designated by the Latin letter V and is determined by the formula:

V = Q / (n/100 x q), Where

Q – heating load (kW/h), q – gas calorific value (kW/m³), n – gas boiler efficiency, expressed as a percentage.

Main gas consumption is measured in cubic meters per hour (m³/h), liquefied gas - in liters or kilograms per hour (l/h, kg/h).

Gas consumption is calculated before designing the heating system, choosing a boiler, energy carrier, and then easily controlled using meters

Let us consider in detail what the variables in this formula mean and how to determine them.

The concept of “heat load” is given in the federal law “On Heat Supply”. Changing the official wording a little, let's just say that this is the amount of thermal energy transferred per unit of time to maintain a comfortable air temperature in the room.

In the future, we will also use the concept of “thermal power”, so at the same time we will give its definition in relation to our calculations. Thermal power is the amount of thermal energy that a gas boiler can produce per unit of time.

The heat load is determined in accordance with MDK 4-05.2004 by thermal engineering calculations.

Simplified formula:

Q = V x ΔT x K / 860.

Here V is the volume of the room, which is obtained by multiplying the height of the ceiling, the width and length of the floor.

ΔT is the difference between the air temperature outside the building and the required air temperature in the heated room. For calculations, the climatic parameters given in SP 131.13330.2012 are used.

To obtain the most accurate gas consumption indicators, formulas are used that even take into account the location of windows - the sun's rays warm the room, reducing heat loss

K is the heat loss coefficient, which is the most difficult to accurately determine due to the influence of many factors, including the number and position of external walls relative to the cardinal directions and wind conditions in winter; number, type and sizes of windows, entrance and balcony doors; the type of building and thermal insulation materials used, and so on.

On the building envelope there are areas with increased heat transfer - cold bridges, due to which fuel consumption can significantly increase

If it is necessary to perform a calculation with an error within 5%, it is better to conduct a thermal audit of the house.

If the calculation requirements are not so stringent, you can use average values ​​of the heat loss coefficient:

• increased degree of thermal insulation – 0.6-0.9;
• medium degree of thermal insulation – 1-1.9;
• low thermal insulation – 2-2.9;
• lack of thermal insulation – 3-4.

Double brickwork, small windows with triple-glazed windows, an insulated roofing system, a strong foundation, thermal insulation using materials with low thermal conductivity - all this indicates a minimum coefficient of heat loss for your home.

With double brickwork, but a regular roof and windows with double frames, the coefficient rises to average values. The same parameters, but single brickwork and a simple roof are a sign of low thermal insulation. The lack of thermal insulation is typical for country houses.

You should take care of saving thermal energy already at the stage of building a house by insulating the walls, roof and foundation and installing multi-chamber windows

Having chosen the coefficient value that best matches the thermal insulation of your home, we substitute it into the formula for calculating the thermal load. Next, using the formula, we calculate gas consumption to maintain a comfortable microclimate in a country house.

Gas consumption using specific examples

To determine what the natural gas consumption will be when heating a one-story house of 100 m2, you first need to determine the heat load.

Heat load calculation

To obtain the most accurate data on the heated volume of the house, the volume of each room and auxiliary premises where it is necessary to maintain heat is separately calculated. Length and width measurements are taken along the baseboards using a regular or laser tape measure.

We will do it simpler: we take the ceiling height as 2.5 meters, multiply it by the indicated area and get the volume of the house V = 250 m³.

If the room has a complex architectural shape, it is divided into rectangles, triangles, circles, the area of ​​each of them is calculated and summed up

To determine ΔT, column 6 in table 3.1 SP 131.13330.2012 is used. The air temperature of the coldest period is indicated here, calculated based on average monthly temperatures.

We find the name of the locality where the heated facility is located. Let's say this is Bryansk, therefore, the desired value is -12 °C. The temperature in living rooms according to GOST R 51617-2000 should be within 18-24 °C. Taking the average value of 22 °C, we get ΔT= 34 °C.

We determine the degree of thermal insulation of the house and apply the appropriate coefficient. In the context of rising prices for coolants, most homeowners strive to increase the energy efficiency of heating by improving the thermal insulation of their home, so it is quite reasonable to use the first indicator of the average degree of thermal insulation, which is equal to 1.

We summarize all the values ​​using the formula:

250 m³ × 34 °C × 1 / 860 = 9.88 kW/h.

Let's apply the rounding rule to the nearest integer and get Q = 10 kW/h.

Don’t neglect automatic control - set different heating modes for night and daytime to ensure a comfortable microclimate regardless of the temperature outside and save up to 30% on gas

Let us remind you that we only did thermal calculation at home and now the next step is calculating gas consumption. But for now it would be appropriate to make a small digression and clarify that the heating load can be calculated in a simplified way.

notice, that gas boiler power can be calculated for a specific object, taking into account all the technical nuances. According to average data, for every meter of standard living space there is 100 Wh of thermal energy. Therefore, for a house with an area of ​​100 m² this figure will be 100 W/h × 100 m2 = 10,000 Wh or 10 kW/h.

In this case, calculations using the formula and the simplified method gave the same result, but this does not always happen, and the difference often reaches 20% or more. Moreover, heating engineers recommend buying turbocharged and atmospheric boilers always with a margin of 20-25% with the expectation of being able to cover heat losses on days with critically low temperatures.

Mains gas consumption

To calculate, you need to know the efficiency of the gas boiler. You can see it in the technical specifications indicated in the accompanying documentation. We will choose a model that is suitable for a house of the specified area.

The main selection criterion will be the thermal power of the unit. Its value is very close to the value of the heat load and can be calculated using the same formula, but for the calculation the temperature of the coldest five-day period is taken into account or an increasing factor of 1.3 is applied, because the boiler must have enough power to maintain heat in the house even in the most severe frosts.

Therefore, for heating 100 m² you will need a boiler with a power of about 13 kW. Efficiency (n) of many models wall-mounted gas boilers, for example, NEVA brand units, is 92.5%. We will use this value in our calculations.

Thanks to the design features of the combustion chamber, increased efficiency of heat exchangers, and the use of latent heat of water vapor, the efficiency of modern gas boilers exceeds 90%

The calorific value, or, in other words, the specific heat of combustion (q) depends on the type of gas used. It is better to check with the gas supply company about what kind of gas is supplied to your home.

By default, we will substitute in the formula the rounded value corresponding to G20 gas with the lowest calorific value Hi, namely 9.5 kWh/m³. Please note the units of measurement are kilowatts, not megajoules.

All the necessary values ​​have been determined and all that remains is to reduce them into the formula:

V = 10 / (92.5 / 100 × 9.5). V = 1.1 m³/h.

Thus, the consumption of main gas when heating a house with an area of ​​100 m² with a ceiling height of 2.5 meters is just over 1.1 cubic meters per hour. Per day, respectively, 24.2 cubic meters.

Now it’s easy to find out how much gas is needed for the entire heating season. According to state regulations, during the heating season the average daily outside air temperature does not exceed 8 °C. In the middle zone, this period lasts from October 15 to April 15 (183 days).

Since significant temperature fluctuations occur at this time, the daily gas consumption is divided by 2 and then multiplied by 183. That is, about 2214.3 cubic meters of main gas will be required for the heating season.

How much propane-butane do you need for the heating season?

Modern gas boilers are designed to use not only main gas, but also liquefied gas. To stock up on the required amount of fuel, they use not ordinary gas cylinders, but more capacious tanks - gas tanks.

The use of gas tanks solves the problem of storing liquefied hydrocarbon fuel sufficient to heat a house of 100 square meters. m, throughout the heating season in a temperate climate zone

When calculating the consumption of liquefied gas required to heat a 100m2 house, the same methodology is used, but the values ​​of some variables in the formula change.

A liquefied propane-butane mixture is supplied for household needs.

Its calorific value is 12.8 kW/kg. We substitute this parameter into the formula and get:

V = 10 / (92.5 / 100 × 12.8). V = 0.8 kg/h.

When operating on liquefied fuel, the efficiency of the equipment decreases, so gas consumption increases by approximately 10% and amounts to 0.88 kg/h per day. The correction may be different for your boiler model. The specific value is indicated in the attached documentation.

Now we calculate the required amount of gas for the heating season: 0.88 × 24 × 183 = 3865 kg. This value must also be divided by 2 due to temperature fluctuations. Final result: 1932.5 kg of propane-butane is required for the heating season.

It will be useful to convert kilograms to liters. Based on reference data, 540 grams of liquefied propane-butane mixture corresponds to 1 liter. That is, for the entire heating season, 3578 liters of liquefied gas will be required.

Conclusions and useful video on the topic

Are you careful about heat energy, but your neighbor still uses less? The author of the video decided to share his own experience of using LPG for home heating. Perhaps this information will be useful to you too.

Do thermostats and temperature sensors really help to significantly reduce gas costs during the heating season? The video demonstrates how this happens in practice.

To determine the upcoming gas consumption for heating, a higher education is not required. Knowing how the simplest mathematical operations are performed, you will calculate the necessary parameters with an acceptable error.

Along the way, you will be able to identify weak points in your home, minimize heat losses, eliminate heat leakage to the outside and, as a result, take advantage of all the benefits of blue fuel.

Please comment on the information we provide with calculation balls and formulas for determining gas consumption. You can share useful information on the topic of the article, ask a question or post a photo in the block below. It is possible that your recommendations will be useful to site visitors.