ᐅ Difference in Initial Costs: Gas System vs. Heat Pump

World-e schrieb:

It won’t work exactly like that. There are plenty of days when there isn’t enough photovoltaic electricity to cover even the base load.
I installed a Geisha (F model) and also experimented with timers, lowering heating at night and raising it a bit during the day. Often, heating didn’t come on at night at all and the house cooled down a little.
None of that really convinced me. The only thing I do is have the hot water generated only between 11 a.m. and 5 p.m. That’s usually enough for us. Of course, it depends on showering habits. Our house and photovoltaic system face southeast, so there’s more sun in the morning than in the afternoon.
There are certainly other photovoltaic-heat pump combinations that communicate better and therefore increase self-consumption rate.
Still, I’m very satisfied with the Geisha, especially for the price of €2500. But you have to do a lot yourself or invest time learning. Or you need a competent and willing heating installer to support you with such an installation.

How much electricity do you have to buy annually for how many square meters of living space?
And what is your seasonal performance factor?

ludwig88sta schrieb:

You mean “Ideally, you heat the water smartly only at midday when the sun is shining on your photovoltaic system, which you then use to heat as needed at night.” Because especially at midday the house shouldn’t be heated in addition to the solar energy it’s getting.

When I think of smart, I always imagine controlling everything over the internet via smartphone, or raising and lowering blinds by smartphone. I usually don’t need that and don’t intend to install it. But to use my own photovoltaic electricity with the heat pump, my house doesn’t need to be smart, right? That should be standard, even without smart technology?

By smart, I meant more intelligently controlled and not necessarily with a smart home system.
That’s along the lines of what World-e described.

I hope that only heat pumps with intelligent ("smart") controls will be installed from now on. Anything else would be a waste of money (at least currently with the feed-in tariff and so on)!?

hegi___ schrieb:

How much electricity do you have to buy annually for how many square meters of living space?
And what is your annual performance factor?

Unfortunately, I can’t provide complete figures yet since we only moved in at the end of February 2019.
KfW40 house with controlled ventilation system
143m² (1540 sq ft) of living space, plus about 70m² (750 sq ft) basement. Everything except the storage room in the basement is heated by underfloor heating. The main bathroom also has wall heating.
Standard outside temperature -16°C (3°F) (postal code 88***)

From 01/01/2019 to 12/01/2019:
Heat produced: 7216 kWh
Electrical consumption: 1867 kWh
Annual performance factor: 3.86

The annual performance factor could probably be higher, but due to the very well insulated house, the domestic hot water preparation has a greater impact on the annual performance factor.

At the beginning, the electric heating element for defrosting was still activated, which consumed a significant amount of electricity. However, it has been off for some time now.

Photovoltaic system: 9.74 kWp
Current figures for 2019 to date:
Photovoltaic production: 11070 kWh
Direct consumption: 1490 kWh
Fed into the grid: 9580 kWh
Electricity drawn from the grid: 2386 kWh (total household electricity)

We have also installed the Geisha (the new model) since early 2018:
- Clean the filter once a year, no other maintenance required
- If it breaks down, you simply buy a new one, around 2500€
- Heating element is disconnected (minus 12°C (10°F) standard for Austria, so relatively mild)
- I haven’t done anything myself except for programming and commissioning

I decided against smart control for the photovoltaic system, in my opinion it doesn’t add value. I make sure it ALWAYS runs during the heating season in the daytime – for me from 9 a.m. until at least 8 p.m. Because then it’s warmer and the sun might shine. At night, when it’s coldest, it switches off depending on the outside temperature for 6 to 11 hours. If it’s very cold, it runs continuously. I adjust the heating curve using a timer for this.

Over the course of the year, photovoltaic contributes maybe about 30% to heating and hot water.

You can also simply let it run 24/7.

boxandroof schrieb:

We have also installed the Geisha (the new model) since early 2008:
- Clean the filter once a year, otherwise no maintenance
- If it breaks down, just buy a new one, around 2500€
- The heating element is disconnected (mild climate according to Norm AT -12°C (10°F))
- I haven’t done anything myself except for programming and commissioning

I decided against a smart control system for the photovoltaic setup; in my opinion, it doesn’t add much value. I make sure it always runs during the heating season in the daytime – for me from 9 a.m. until at least 8 p.m. Because it’s warmer then and the sun could be shining. At night, when it’s coldest, it switches off depending on the outside temperature for 6 to 11 hours. If it’s very cold, it runs continuously. I adjust the heating curve using a timer for this.

Over the year, photovoltaic contributes about 30% to heating and hot water.

You can also simply run it 24/7 if you prefer.

But you sourced it yourself? Through a heating installer it would probably be more expensive.

I bought them myself, but only because I couldn't find anyone willing to sell and install them for me. I would have paid more otherwise.

The heating engineer did everything else: underfloor heating and hydraulics – basically everything inside the house – and kindly also installed the two water-carrying pipes up to the heat pump outside. Of course, this is excluded from the warranty and so on.