Poultry house energy demand calculator
How much heating power does a house need on the coldest day? Heat demand depends on losses through the building envelope (walls, roof, floor), ventilation losses and the temperature difference between inside and outside. We show a simple formula and a worked example so you can size heaters and estimate the season cost. You will compute the exact figure for your own house in the app after signing up.
verifiedFrom the team that has organised work on poultry farms for years.
What we calculate and why
A poultry house energy demand calculator answers a simple question: how much heat escapes the building in frost and what heating power must be supplied to hold the target temperature. This is the basis for sizing heaters and estimating the heating-season cost. The result matters most during brooding, when the first days need as much as 32-34°C — the start temperature calculator will help you set the required value.
Three sources of energy demand
Energy in a house goes to three things: heating (most in winter), ventilation (fans run all year) and lighting (the light programme). Heating closes the heat balance — it tops up the losses the birds’ own heat cannot cover. Ventilation removes moisture, ammonia and surplus summer heat, but in winter it also draws out warm air, so its share of losses is real. We cover air-exchange rules in the guide on broiler house ventilation.
The formula in words — envelope plus ventilation
Heating power demand is the sum of two parts. The first is envelope loss: for each wall, the roof and the floor you multiply the area by the heat transfer coefficient U (the lower the U, the better the insulation) and by the temperature difference inside minus outside. The second is ventilation loss: the exchanged airflow times the air heat constant (about 0.34 Wh per cubic metre per degree) times the same temperature difference. The sum gives power in watts, which we convert to kilowatts.
Why know the heating power
With the result you size heaters of the right power (with a margin for the coldest day), calculate gas or electricity use and the cost of the whole season. It is also the starting point for decisions on insulation and heat recovery — sometimes better insulation is cheaper than a bigger burner. A fuller picture of heating costs is in poultry house heating costs, and a way to recover heat from exhaust air is described in heat exchangers in the house.
How to calculate poultry house energy demand — six steps
From gathering building data to the result in kilowatts and the season cost. We calculate heating power demand on the coldest day — that peak decides the heater sizing.
Gather building data
Note the envelope areas (walls, roof, floor in square metres), the U insulation values for each, the target inside temperature and the design outside temperature (coldest day, e.g. −20°C), and the air exchange in cubic metres per hour from the guide on house ventilation.
Write the formula
Heating power = (Σ area × U × Δt) + (airflow × 0.34 × Δt), where Δt is the inside minus outside temperature difference and 0.34 is the specific heat of air in watt-hours per cubic metre per degree. The first bracket is envelope loss, the second is ventilation loss. The result comes out in watts.
Insert example data
A house of 1200 m² floor, walls 480 m² at U = 0.35, roof 1200 m² at U = 0.25, floor U negligible. Target 20°C inside, −20°C outside, so Δt = 40°C. Minimum winter ventilation 6000 m³/h. This is a realistic but illustrative data set — yours will differ.
Substitute into the formula
Wall loss: 480 × 0.35 × 40 = 6720 W. Roof loss: 1200 × 0.25 × 40 = 12000 W. Envelope total ≈ 18720 W. Ventilation loss: 6000 × 0.34 × 40 = 81600 W. Sum: 18720 + 81600 ≈ 100320 W, that is about 100 kW of peak demand.
Read the result
About 100 kW is the heating power needed on the coldest day at minimum ventilation. In practice you size heaters with a 15-20% margin. You compute fuel use by dividing energy by the calorific value (natural gas about 9.5 kWh/m³, propane about 12.8 kWh/kg) and multiplying by the price from the current tariff.
Use the result
You translate the kW into heater sizing and an indicative season cost (kW × running hours × energy price). The full cost analysis is in poultry house heating costs, and a heat exchanger cuts ventilation losses. In the app you compute this for your house and save it in the digital Flock Card.
Norms, prices and common calculation mistakes
A calculator result is only as good as its inputs. Here are six tips to compute the demand soundly and neither overestimate nor undersize the power.
Typical U-values
The heat transfer coefficient U tells you how much heat escapes through a square metre of the envelope per degree of difference (W/m²K). For a well-insulated house wall it is usually 0.25-0.40, for a roof 0.20-0.30, and for thin, poorly insulated sheeting even above 1.0. The lower the U, the smaller the losses — so insulation pays back over the whole life of the building.
Insulation and airtightness
Two houses of the same area can differ in demand by a factor of two if one is well insulated and tight and the other is not. Leaks (doors, inlets, roof) are uncontrolled ventilation that chills the building in winter. Before the season it is worth sealing the house and checking the insulation — that is cheaper than adding heating power.
Share of ventilation losses
In the example, ventilation accounted for over 80% of losses — that is typical, because air exchange is required for moisture and ammonia and cannot be switched off. So the biggest heat saving comes not from a bigger burner but from recovering heat from exhaust air (heat exchanger) and precise control of minimum winter ventilation.
Energy prices — use current ones
The season cost depends on the price of gas, propane or electricity, and these change. Use current, public supplier tariffs, not figures from years ago. For the calculation take the fuel calorific value and the device efficiency (gas heaters 90-100%, but some heat escapes with flue gases). The full cost breakdown is in poultry house heating costs.
Common mistakes
The most frequent errors are: counting only wall losses and ignoring ventilation (which dominates), using an average temperature instead of the design coldest-day one (then heaters are too weak), confusing U with insulation thickness, and leaving no power margin. Remember too that birds give off heat — in a full flock the heating demand is lower than in an empty house.
Calculate in the app
A manual sum is fine for a rough estimate, but for your own house it is easier in the app: you enter dimensions, insulation and ventilation, and the calculator returns power in kW and the season cost. You link the result to a specific flock in the digital Flock Card, and the reports to flock records in IRZplus DlaFerm.pl will send for you, if you want — so you get the full picture of the cycle in one place.
Frequently asked questions about poultry house energy demand
How do I calculate the heating power a house needs?add
Add the envelope losses (area of each wall, the roof and the floor times the U-value times the temperature difference) and the ventilation losses (exchanged airflow times 0.34 times the same difference). The sum in watts, divided by 1000, gives the power in kilowatts. Calculate for the coldest design day, not the average, because the peak decides the heater sizing.
What weighs more on the balance — wall losses or ventilation?add
In a typical house in winter, ventilation losses dominate, often over half, and at intensive air exchange even 80%. This is because air exchange is required for moisture and ammonia and cannot be switched off. So the biggest savings come from recovering heat from exhaust air and good control of minimum ventilation, not just thicker wall insulation.
What is the U-value and what values are typical?add
The heat transfer coefficient U tells you how many watts escape through a square metre of the envelope per degree of difference (W/m²K). The lower it is, the better the insulation. For a well-insulated house wall it is usually 0.25-0.40, for a roof 0.20-0.30, and for thin, poorly insulated sheeting even above 1.0. The U-value comes from the insulating material data and its thickness.
How do I calculate gas use for heating a house?add
First calculate the heat energy needed over the season (power times running hours), then divide it by the fuel calorific value: natural gas is about 9.5 kWh per cubic metre, propane about 12.8 kWh per kilogram. Account for device efficiency, since some heat escapes with flue gases. Usage times the current tariff price gives the season cost.
Do birds lower the heating demand?add
Yes. Birds give off heat, so a full flock needs less energy for heating than an empty house. That is why the start with chicks is the hardest: the flock is small, gives off little heat, and the target temperature is the highest in the whole cycle. As the birds grow their own heat rises and often you have to cool more than heat.
What power margin should I take when sizing heaters?add
Usually 15-20% above the calculated peak demand, to have a margin for frost sharper than the design value, leaks and fast warm-up after airing. Too little power means a chilled flock in frost, while heavy oversizing means needless equipment cost. A good compromise is a sound loss calculation plus a sensible margin, not blindly enlarging the burner.
Calculate poultry house energy demand in DlaFerm.pl
Want to quickly size heaters and estimate the season cost for your own house? After signing up you compute the heat demand in the app and link the result to a specific flock in the digital Flock Card. Create a free farm account.
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