ᐅ Heating System Upgrade for Existing Buildings – Condensing Boiler / Air-to-Water Heat Pump / Air Source Heat Pump

Created on: 9 Apr 2022 10:12
C
Chrizz72
Hello dear forum,

I am new here and this is my first post. I would be very grateful if anyone could help me with my question/problem.

Starting point:
We are about to buy a single-family house (built in 1959/60; living area approx. 170sqm (1830 sq ft) – 65sqm (700 sq ft) first floor, 65sqm (700 sq ft) second floor, 40sqm (430 sq ft) attic). The windows were replaced in 2005 (Uw-value 1.2), we will reroof and insulate the roof (U-value 0.14), possibly also insulate the basement ceiling – everything else is still in the “original condition.” Four of us will live in the house (2 adults + 2 children). The attic will be converted into living space. There is an old gas boiler (not condensing) in the basement and old cast iron radiators throughout the house. Additionally, we will renew the electrical system and renovate all the floors.

The key question now is: What heating system should we choose?
Since the house was previously occupied only by an elderly lady, there is no reliable data to estimate our future heating demand. Naturally, we would prefer to move away from fossil fuels and install an air-to-water heat pump combined with underfloor heating and photovoltaic panels (without subsidies, this would definitely cost about 65K) – however, this would exceed our budget. Without photovoltaic, I am also quite worried that the electricity costs could skyrocket. As a compromise, we have now focused on the following option: installation of a gas condensing boiler for heating and a domestic hot water heat pump (DHW HP) for hot water production – the ability to reduce the condensing boiler’s use during warmer months seems very attractive. Besides the cost aspect (which is completely acceptable to us, both initially and ongoing), the sustainability aspect also plays a role here (of course, a DHW HP alone is not a huge lever). At the same time, we are thinking about switching to underfloor heating on the ground floor and low-temperature radiators on the first and second floors. The idea behind this is to create an infrastructure that would allow us to switch to a heat pump fairly easily in the future. We would also gain reliable data regarding heat and heating demand. We wouldn’t have to install photovoltaic on the roof immediately but could add it later, either gradually or all at once.

How do you assess my approach? Does it sound realistic and reasonable to you, especially considering the current context (war, energy transition/costs, etc.)? I understand there is no perfect solution, but I would like to make a well-informed decision that makes economic and ecological sense in the short and long term. Maybe there are alternatives I haven’t considered yet.

A little about me: I am unfortunately not very skilled technically and have very little experience. However, I have noticed that I can quite quickly get to grips with unfamiliar topics and have a steeper learning curve than expected 🙂

I look forward to your feedback.

Best regards,
Christian
C
Chrizz72
15 Apr 2022 12:52
Deliverer schrieb:

If it’s not an issue—and it probably isn’t—for the bedroom to be one or two degrees cooler than the floor below, then that works out perfectly. The heating circuit can be connected directly to the supply line of a small heating loop without any efficiency-reducing mixing.

It’s like with many things: once you understand the rules (and the reasons behind them), you can sometimes break them. ;-)

Edit: Additional idea: install an air conditioner in that room. It helps with sleeping well in summer, can cool the floor below to some extent when doors are open, and in emergencies, it can also provide heating upstairs.

Exactly!

The many helpful comments here definitely helped me with my decision-making. Great forum!!
LeonBerentSter21 Jun 2022 10:49
Hello,

I am a journalist working on a story about "New Heating Systems" for Capital Magazine. I would like to speak with homeowners who are currently considering what option makes the most sense for them. Would you be interested in discussing this with me? It would be very helpful. Anonymity is also welcome.

Kind regards,

LeonBerentSter