Many factors influence the costs of heating a home: energy efficiency of the building, type of insulation, house size, heating system type, and in the case of stoves, the type of fuel used. Annually, differences between various heating systems can amount to several thousand złotys! Therefore, when building a home, it's worth considering the choice of a more expensive system that will result in lower costs in the future.
Table of Contents:
Home Heating Demand
What Contributes to the Cost of Home Heating?
Comparison of Heating Costs for Different Systems and Fuels
How to Reduce Heating Costs in an Older Home?
The energy demand of a building is expressed in kilowatt-hours per square meter of floor area. Typically, demand is given on an annual basis. Passive houses have the lowest demand (15 kWh/m2), followed by energy-efficient homes (50 kWh/m2). Houses with quality insulation range from 60 to 100 kWh/m2. In the case of older homes, energy demand can be much higher, even exceeding 150 to 200 kWh/m2.
Each fuel has a specific efficiency expressed in kilowatt-hours. For fuels, values are given in kWh/kg, while for natural gas and oils, it's 10 kWh/m3. Knowing the energy demand of the house allows us to calculate how much fuel will be required to heat the house. Furthermore, knowing the fuel price (per m3, kg, or kWh) enables us to determine the exact cost of heating. However, there are many more calculations involved.
We now know that the cost of home heating is essentially the cost of fuel needed to produce a certain amount of energy according to the house's demand. Yet, other factors come into play, such as the house's shape. Simple rectangular houses will lose more heat than complex houses with balconies, bay windows, and dormers. Each such element creates a risk of thermal bridges. Additionally, the technology of wall construction, type of building materials, and insulation used also contribute.
Each heating system has a specific efficiency that informs us how much energy the system will be able to utilize for heating the house. For example, if an 80% efficient furnace uses only about 4 kWh from a kilogram of pellets, even though that fuel offers up to 5 kWh from each kilogram, then weather conditions come into play. A long, cold winter will result in higher heating costs compared to a short, warm winter.
Alright, now that we understand the factors contributing to the cost of home heating, we can point out the differences between various heating systems and fuels. Let's use the example of a new, insulated house with an energy demand of 100 kWh/m2. Here's the annual heating cost breakdown:
Heat Pump – from 2500 to 3000 zł,
Wood-burning Stove – about 3500 zł,
Coal-burning Stove – from 4000 to 5000 zł,
Pellet-burning Stove – about 5000 to 5500 zł,
Natural Gas Furnace – from 4200 to 4500 zł,
Liquid Gas Furnace – about 6500 zł,
Oil Furnace – about 6500 to 7000 zł,
Electricity in G12W Tariff – over 6,000 zł,
Electricity in G11 Tariff – even over 10,000 zł.
Heat pumps come out on top, and it's no surprise that they're finding increasing use in homes. They also constitute the biggest expense in terms of system purchase and installation cost, but it's easy to notice that in an annual context, a heat pump can offer savings ranging from 1000 to even 4,000 zł, making this choice pay off fairly quickly. Especially since a heat pump can be powered by renewable energy from sources like photovoltaics. Here, it's also fair to acknowledge that electric systems fare much better in homes with photovoltaics. Therefore, the cost of home heating should always be evaluated holistically.
While the heat demand of new homes is typically below 120 kWh/m2 annually, older uninsulated homes can reach over 200 kWh/m2. Heating expenses in an older home can be up to three times higher compared to a new energy-efficient home. Therefore, it's worth considering how to reduce the heating costs of such a house.
Prioritizing insulation is crucial. Only with good insulation can heating costs be lowered by even half. Next, upgrading to better and more energy-efficient windows and exterior doors is valuable. At the same time, consulting professionals to assess the roof and identify potential thermal bridges, which cause the most heat loss, is worthwhile. After a major renovation, it might be a good idea to consider changing the heating system. Subsidies are available for all these works, and thermal modernization tax relief also applies.