A client called us last winter with a simple but loaded question: "The house is basically decided - but what do I actually heat it with?" It's the one decision Treevia deliberately leaves open. Every house leaves our production hall with underfloor heating distribution and heat-recovery ventilation already installed. The heat source itself - the thing that actually generates the warmth - is yours to pick, sized to your plot, your budget and how you plan to live in the house.
The trouble is that "heat pump" isn't one product. It's a category with wildly different price tags, efficiencies and installation demands hiding under the same two words.
Air-to-water heat pump: the default choice
This is what most Treevia owners end up installing, and for good reason.
- COP: 3.5-5.0
- Cost: PLN 25,000-45,000
- Works directly with underfloor heating
- Best all-round choice for most modular houses
Ground-source heat pump: the quiet, expensive overachiever
If your plot allows for drilling or ground collectors and your budget has room to stretch, this is the most stable performer on the market.
- COP: 4.0-5.5 (the most stable of the three)
- Cost: PLN 40,000-80,000, including drilling or collectors
- Requires ground works before the house even goes up
- Best efficiency available, but also the highest upfront investment
Air-to-air heat pump: useful, but not enough on its own
- COP: 3.0-4.5
- Cost: PLN 8,000-15,000
- Heats air directly, with no water installation involved
- A good supplement, but not a sole heat source in the Polish climate
Why the pairing with a modular house works so well
None of these numbers matter much if the building itself leaks heat. A Treevia house is engineered to need very little energy in the first place, thanks to:
- Multi-layer wall insulation (U < 0.15 W/m²K)
- Airtight construction, verified with a Blower Door test (n50 < 1.5)
- Recuperation that recovers 85-95% of exhaust heat
- Low U-value windows (0.7-0.9 W/m²K)
Put a heat pump behind that envelope and it barely has to work.
What does it actually save you?
Take a 120 m² house, the BARN 124, as the reference point.
Gas boiler + radiators (traditional):
- Gas consumption: 1,500-2,000 m³/year
- Cost: PLN 7,000-11,000/year
Heat pump + underfloor heating (Treevia):
- Electricity: 3,000-4,500 kWh/year
- Cost: PLN 2,000-3,000/year
Savings: PLN 5,000-8,000 a year - figures that should be read as an illustration of the mechanism, not a guaranteed bill for every household, since usage habits and local tariffs vary.
The bottom line
Treevia's job is to hand you a house that's already prepared for efficient heating - underfloor distribution, recuperation, U=0.15 insulation. Your job is to pick the source that fits your plot and your wallet. Talk to us before you sign anything with an installer; we can tell you fairly quickly which option makes sense for your specific model and location.