ᐅ Experience, ongoing costs of the Rotex HPSU Compact 308

Hello everyone,
I have received a quote from the developer (Heinz von Heiden) for my planned house (Arcus 160 - 152.57 m² (after WoFIV) and 164.79 m² (after DIN 277)).
It is a combined unit (water tank and indoor unit integrated).
According to the offer, the unit is designed for 170 m² (1,830 sq ft).

- What are your opinions?
- My friend thinks that the indoor unit will need repairs or maintenance again. If it is combined with the water tank, it might be difficult.
- What has your experience been with this type of unit so far?
Thank you for your answers.

Forget that quote... Designing a heating system based solely on square meters of living or heated area is completely wrong. That’s just sales talk or a sales calculation. For example, would a heat pump sized for 170 m2 (1830 sq ft) of living space be enough to heat a house on the Zugspitze, in Cologne, Alaska, or the Congo? Make sure the heat pump is sized according to a proper heat load calculation and the underfloor heating design. And don’t let the system be oversized.

We have had a system like this from Heinz von Heiden in operation for 5 months now, including cooling functionality.

So far, it does what it is supposed to do. It would be bad if it didn’t. I can’t really say much more yet—neither positive nor negative.

Regarding the design of such a heating system: I think relating it to the living area is easier for the average user to understand than heating load. This approach will probably cover 85 to 90% of cases, especially when preparing a quotation. For the building permit / planning permission or the energy performance certificate, a detailed calculation must be provided anyway, right?

There is a database for real energy consumption of heat pumps, similar to Spritmonitor, which you can find through your search engine. Its reliability is limited to specific conditions, but it provides a useful reference point.

The heat pump should not be oversized, and the surface heating system should be optimized for the lowest possible supply temperatures. For this, a room-by-room heating load calculation is used. Ideally, you should also specify your desired room temperatures (is 24°C (75°F) required in the bathroom according to the standard?). Request this calculation and the resulting maximum supply temperature early on, so you know what to expect. More than 35°C (95°F) is not allowed in new builds, and a target of up to 30°C (86°F) should be aimed for. Avoid buffer tanks and individual room controls. You can find a lot of information on all these topics online from other homeowners.

Winjoe1 schrieb:

For the building permit / planning permission or the energy performance certificate, a detailed calculation must be submitted anyway!??

No, the certificates have little to do with the actual heating system design, as @lesmue79 has pointed out. Construction companies often take the easy route here at the expense of homeowners and make rough estimates. It’s better to err on the side of a slightly larger system, so the homeowner never feels cold.

Just for your information. Starting January 2020, ROTEX will become Daikin. It seems Rotex had a trademark dispute with Daikin?!