How does Apex Heat calculate the profitability of an investment?

9/17/2026

What does a heat pump cost and save?

In a typical detached house a ground-source or air-to-water heat pump costs around 10,000 to 30,000 euros and saves 1,500 to 3,000 euros a year in heating costs. With a ten to fifteen year loan the loan payments can stay below the saving, so the annual heating cost falls from the first year.

In apartment buildings and commercial properties heating is usually 1 to 2 €/m² per month of a maintenance charge of 5 to 6 €/m² per month. The heating share can fall by up to 70 percent, on average about one euro per square metre, by switching to a ground-source or air-to-water heat pump. The investment is typically covered by a capital charge of 0.5 to 1 €/m² per month, so the monthly cost falls immediately.

Where does the saving come from?

A heat pump moves heat from the ground or the outdoor air indoors instead of producing it by burning fuel or with a resistance heater. Its efficiency is stated as a COP: a COP of 4 means one kilowatt-hour of electricity delivers four kilowatt-hours of heat. The calculation uses a seasonal coefficient of performance, computed hour by hour from the outdoor temperature.

If the building has electric heating, its electricity consumption falls by the efficiency ratio for the heating share. Otherwise electricity consumption rises, but the need for district heating or oil disappears. The saving is the difference between those costs at the building's own energy prices: the electricity spot price and distribution tariff, the district heating company's price list or the fuel price. The heat pump's maintenance costs are included.

Electricity usually costs more per megawatt-hour than district heating or oil, so a pump saves only when its seasonal efficiency exceeds the price ratio. In an apartment building in Helsinki where district heating costs 100 €/MWh and electricity 116 €/MWh, an air-to-water heat pump with a seasonal efficiency of 2.08 delivers heat at 56 €/MWh. Read the full example.

How are net present value and the recommendation calculated?

Net present value is the present value of the savings over the investment's lifetime less the investment cost. The discount rate is the property yield of the building's location or, where none is available, 7 percent; the user can set it themselves. A positive net present value means the investment returns better than the discount rate. Profit typically starts to accumulate after a payback time of about ten years, and energy investments last for decades.

The recommendation is the solution with the largest net present value among those that can be built. Ground-source heating is left out of the comparison if the required boreholes do not fit on the lot or drilling is prohibited by the zoning plan. The figures for the excluded solutions are still shown.

For comparison: where a savings account yields 0.5 percent, a low-risk fund 2 percent and a residential property investment 4 percent, the annual return on a heat pump investment can exceed 10 percent, and there is always demand for heat.

How is the profitability of added insulation calculated?

Heat losses are recalculated assuming the insulated structure meets the current low-energy building requirement, and the saving is the price of the difference in losses. Compared with the regulations of the turn of the millennium, current windows cut window heat losses by more than half, added roof insulation by 60 percent and added wall insulation by 40 percent; in older buildings the difference is larger.

Profitability depends on the cost of the structure. Blowing extra insulation into a pitched roof's attic is cheap and often profitable. Added wall insulation usually requires renewing the cladding, so it is best timed with a facade renovation that is needed anyway. Replacing windows and doors is easier and also improves draught-proofing and sound insulation. Ventilation losses are reduced by heat recovery where the building has mechanical ventilation.

How is the profitability of solar power calculated?

In Finland solar panels usually cover 10 to 20 percent of annual electricity consumption, because irradiation is concentrated between April and September. In a detached house that is an annual saving of a few hundred euros.

Profitability is decided by how much of the production is consumed on site. Self-consumed electricity is worth the full electricity price including distribution and taxes, while electricity sold to the grid earns only the energy price. The calculation combines the building's hourly electricity consumption with local irradiation data and sizes the system so that the self-consumed share stays high. With a heat pump the share grows, because the pump's consumption and the production partly fall in the same hours.

What does the profitability calculation not take into account?

The calculation does not know the owner's financing terms unless they are entered, and it does not price living comfort, the rise in resale value or emissions in euros. Emissions are calculated separately. Without measured consumption the saving is a modelled order of magnitude, not a kilowatt-hour-exact figure. Read why the calculation can be trusted.