ᐅ Heating System for New Single-Family Home: Air-to-Air or Air-to-Water?

I upgraded from a conventional heating system to a condensing boiler in my first house. I can’t provide precise figures regarding the actual benefits.

The issue is that condensing technology only reaches its full potential when you have a as low as possible return temperature. This means that unless you perform a hydraulic balancing combined with reducing the flow temperature, a condensing boiler will hardly provide any advantage.

For this, insulating pipes in the basement, for example, is a simple measure.

I would recommend continuing to use the old heating system as long as it’s not mandatory to replace it and it’s still working properly. Use this time to optimize the overall system, which will allow you to save money with a relatively low investment.

@Joedreck
Thank you for the information. Often, someone who has recently installed something new is so enthusiastic that they no longer report objectively or do the calculations carefully.

My main issue is with the return flow. Despite having underfloor heating, I run a high supply temperature because I used copper pipes back then. I had some problems with plastic tubing, which is why I chose copper. Since copper might react with the concrete, I used plastic-coated copper pipes at the time. To compensate for the expansion coefficient, there is some air space between the copper and the coating, which results in poorer heat transfer but has proven reliable.

To ensure sufficient flow in the more remote areas, I have to run the system a bit faster, which means the return temperature is not very low. The radiators in the basement were never installed because it turned out they were unnecessary due to the lack of insulation. In other words, I heat the basement automatically.

Since I chose a cast iron boiler (no corrosion) back then, it is still almost like new.

I was able to solve the efficiency issue (over the years, the exhaust loss requirements changed from about 14% to now around 10%) quite cleverly. The trick wasn’t even known to the chimney sweep, and heating suppliers said it wouldn’t work.

Now I meet the requirements (down to 8%!), so the chimney sweep just checks it off. It’s a simple and inexpensive solution that only requires some DIY skills.

I’m now thinking beyond condensing boilers even though I initially leaned that way because of oil prices. The 80-meter (260 feet) deep drilling for about 9,000 was initially overwhelming, and digging up my garden with pipe coils at 1 meter (3 feet) depth is too much work.

"Just" dividing the drilling cost over 15 years equals about 600 per year, and I’d save quite a bit of oil.

—Side question: Doesn’t the drilling cool down over the years, which would reduce efficiency?—

By the way:
If anyone reading this has an older boiler whose performance is starting to slip, I’d be happy to share the “super solution” with details.

Greetings from a “searcher” who is open to the future but not very enthusiastic about a 15-year payback period—especially since I know from experience that within that time, several repairs will come up that weren’t originally expected...

So, if you have already done everything possible in terms of optimization, switching to a condensing boiler is almost certainly not going to be cost-effective.

Since you seem to be skilled with DIY, you could install pipes for a wall or ceiling heating system each time you renovate a room. This way, you might have the option to operate a heat pump economically in the future, if your oil heating system fails.

Yes, my optimization ideas are now also focusing on the exterior wall (25cm Ytong) but the effort is quite high (even with self-installation) if I add the polystyrene insulation on the outside. Possibly with a brick veneer finish to avoid plastering. I am currently calculating the financial effort and to what extent it is worthwhile. My interest in this also comes from an extension project and the associated overall visual design.

The tip about wall/ceiling heating was new to me, as I only knew it as electric heating—and electric heating is generally the more expensive solution overall. Pipes in the ceiling or wall are apparently a bigger deal (dropping the ceiling, building out the wall). I need to look into that. Heat rises, so when does the heat from the ceiling reach the floor?

I already posted that underfloor heating and tiles (in the living area—which is great for cleaning and looks but…) are problematic during transition seasons since, unfortunately, we do not live in Sicily. It’s warm during the day, but in the evening, the tile radiates cold since it is unheated. The heating stays off during the day, and if you turn it on in the evening, the floor stores the heat until the next day, making it “super warm” during the day. It works but is hard to control with automatic systems!

Unfortunately, it’s not so easy to plan an overall concept, especially when keeping an eye on the cost!

I have already planned a few flat-plate solar collectors for hot water as the effort is not that big, and I have practically seen what the sun can do. Photovoltaics, however, are a different matter and require longer-term thinking. The possibly optimal solution with storage technology seems to be financially more suitable for people doing it as an expensive hobby.

I recently saw on YouTube that there is something "new" again! Wood stoves with attached pellet elements. They convert heat directly into electricity. This is being marketed as a “super solution.” I am familiar with these elements (they can work the other way around for cooling) because I know them from computer CPU cooling, where they work. But generating electricity using a wood stove? You don’t even need to question it—you should just forget about it!

Fortunately, winters have been getting milder (climate catastrophe has its advantages (irony intended!), let’s hope it stays that way). Greetings from someone who owns warm, thick jackets and still remembers -18°C (0°F)!

In recent weeks I have been thinking about donating these jackets to homeless aid.

But for now, I will first calculate the cost for adding the polystyrene insulation…

What are your supply and return temperatures? Oil consumption and postal code?
Solar water collectors are complete nonsense.

Höhlenmensch schrieb:

Heat rises, so when does the heat from a ceiling heater reach the floor?

A ceiling heater works differently than underfloor heating. Underfloor heating primarily operates through convection, while a ceiling heater functions by radiation.