ᐅ New Heat Pump for an Older Home Without Renovation

xMisterDx schrieb:

Even if the gas price settles at 15 cents/kWh and electricity drops to 30 cents, and you manage to reach a coefficient of performance of 3, I would be very surprised. With a flow temperature of 50°C (122°F) using underfloor heating, an air-to-water heat pump can hardly achieve more. Unfortunately, physics can’t be bypassed, not even by Panasonic.

But anyone can easily calculate this for themselves. In the "old" house, with, say, 16,000 kWh of gas, you pay €2,400. With a factor of 3 for the heat pump, heating costs would be €1,600. That’s a difference of €800 per year. Over 20 years, that amounts to €16,000. Considering annual price increases of 3–4% (and/or substantially rising CO2 charges), it’s worth considering whether the heat pump makes sense. If it costs €20,000 and I receive 30–45% subsidies (no idea how they will develop next year), then the scales definitely tip strongly in favor of the heat pump.

And if you also factor in the alternative investment—“the old oil/gas heating system will have to be replaced anyway”—then there is really no way around the heat pump.

Alessandro schrieb:

Air-to-air heat pumps (ductless mini-split systems) in new builds are definitely the future! No one really needs a heat pump with an efficiency standard like EFH40.
Ductless mini-split systems can also provide effective cooling in the summer.
No more complicated hydraulics with pumps, buffer tanks, etc., more space in the utility room, much cheaper and more convenient (since you can also run an effective ventilation system here).
If I were building a new house, I would only install air-to-air heat pumps.
I would use tankless water heaters for hot water.

If only these systems weren’t always so ugly :p

However, you didn’t take into account the heating industry lobby. Buildings are deliberately made complex with all sorts of extras, even if you only end up with heating costs of 65€ and then maybe 58€ per month. They do the calculations in a way that benefits them. Energy consulting is often just a sales pitch!

Yes, I am partly on the side of this lobby.
This topic has already reached us.
The current issue is the outdoor units, which can be combined with a maximum of 5 indoor units.
Also, I cannot install an indoor cassette unit in bathrooms.
But there are solutions even for this.

For all the options we have calculated (heating only), the air-to-air heat pump (by which I always mean split air conditioning units) is leading.
When it comes to heating, everyone thinks of the installer, who in many cases, of course, does not have a refrigeration license.

The seasonal performance factor is comparable with an air-to-water heat pump.

We have also planned and equipped renovation projects with it. It works smoothly and is a good hybrid option.

Alessandro schrieb:

Air-to-air heat pumps (ductless split systems) in new builds are definitely the future! With an efficiency standard like EFH40, no one really needs a heat pump.

An air conditioner is essentially just a heat pump—with various advantages and disadvantages (which should not be overlooked!). However, this thread is about existing buildings. These include approximately 15 million detached houses built before 2010, as well as 3.5 million multi-family homes, most of which are not energy efficient.

That is exactly why I mentioned that we have already completed projects in existing buildings using this solution. The old heating system remains in place and serves as peak load coverage.

I have a KFW55 house with solar hot water and gas heating (8600 kWh gas/year for heating and hot water) and underfloor heating. The new 6.8 kW split air conditioning system with 4 indoor units is currently used for heating. Managing peak load is one thing, but I plan to turn off the air conditioning at -10°C (14°F) and switch to gas instead.

This is optimal: the gas boiler then operates efficiently in its ideal condensing range. The heat pump in the air conditioning system runs efficiently at moderate temperatures. I can calculate when each option is more cost-effective based on my electricity and gas rates.