ᐅ Underfloor heating and mechanical ventilation with heat recovery, replacement of standard radiators

Der Da schrieb:
So, we chose gas heating for two reasons... we don’t like underfloor heating because of "warm feet" and a heat pump would have cost us $12,000 more. But of course, this is always individual, and we also got a special deal that made gas a bit cheaper. And a third fact: we love cooking with gas... so we hit several birds with one stone

Hello,

with underfloor heating operated by a heat pump, you won’t get "warm feet." If the floor is around 25°C (77°F), that is significantly cooler than your body temperature, so it doesn’t feel warm. An additional cost of $12,000 for a heat pump including drilling might be accurate. The drilling at our place, including connection and filling, cost about $8,500. However, this investment usually pays off over the lifetime of the house.

Regards...

Perlenmann schrieb:
The prices always seem to vary quite a bit.
The drilling (2x60m (2x197 feet)) cost me 4,000€. The gas connection was much cheaper at around 2,000€, and the placeholder heating system was also omitted!
And the warm floors from the underfloor heating are still from the time when the system ran with high supply temperatures!

Hello,

you got a good price for the drilling. For us, also 2x60m (2x197 feet), it was nearly 8,500€ including the complete trenching, penetration through the basement wall, connection to the heat pump, filling with brine, and commissioning of the heat pump. It was hard rock (gneiss), but the price was fixed in advance.

Best regards...

Best regards...

There is no offer available. This is from a general building brief of a specific single-family house manufacturer.
The energy standard should be KfW 70 or 55.
By high operating costs, I mean the electricity costs for the heat pump. You really need true professionals for that, otherwise it can become quite expensive.

Proper planning is necessary for every heat generator.

Why wouldn't that work? They are probably separate heating circuits. You should be able to control them individually.

Due to the controlled ventilation with heat recovery, there is a constant air exchange, making large temperature differences not feasible.

I have also heard that the drilling costs are very expensive. Around €15,000 is quite common. You could heat with gas for a long time for that.
I once considered an air-to-water heat pump, but I have heard too many negative opinions about it.

You cannot generalize the costs for drilling. 2 x 100m (330 ft) will definitely be more expensive than 2 x 60m (200 ft). Furthermore, it depends on what services (connection to heat pump, etc.) are included.

This only concerns the hot water. What about heating if it actually runs constantly during winter? What will the consumption probably be?

Yes, correct, hot water for 4 people, daily showers. What use are my heating costs if your house, area, desired temperatures, or region (AT) are totally different? Have your heating demand calculated precisely, then more can be said about the heat generator.

Regards...

phobos schrieb:
Hi!

What does WE actually mean?

Suppose I’m building with a general contractor (GC) single-family home (SFH) manufacturer. Do they calculate the heating load for my house beforehand, or do they just install a standard off-the-shelf gas condensing boiler?
And what happens if I want underfloor heating instead of regular radiators? The heating system sizing must change then, right?

Hello,

WE = heat generator

I can only tell you how it was for us. We contracted the entire heating system ourselves. The heating engineer had the technical data from the house (manufacturer), such as area, U-values, etc. From us, he received the desired temperatures, number of occupants, and so on. Then he calculated the heating load. The size of the heat pump and the drilling depth were based on that.
I imagine that the SFH manufacturer, especially with all-inclusive offers, installs a standard off-the-shelf system based on various experience values—of course depending on house size, model, location, and so on. However, as often mentioned in forums, caution is advised here because consumption figures can be “adjusted” and calculated values are sometimes unrealistic in practice.

Of course, the choice between radiators and underfloor heating is important for the heat generator and its sizing. Operating a heat pump with radiators is usually not ideal because higher flow temperatures are required. With underfloor heating, the flow temperature should not exceed 35°C (95°F). That’s why underfloor heating, as a type of surface heating, is basically a prerequisite for using a heat pump.

Best regards…

phobos schrieb:
What does WE actually mean?

Heat generator.

phobos schrieb:
...Suppose I build with a general contractor and a single-family house manufacturer. Do they calculate the heating load for my house in advance or do they just install a standard gas condensing boiler?

They usually install a heating system that somehow and solely produces heat. This can lead to absurd system concepts, for example, KfW 70 standard with an air-water heat pump! The focus here is on sales according to their own calculations. Energy efficiency or cost-effectiveness for the builder are mostly disregarded.

phobos schrieb:
...And what if I want underfloor heating instead of standard radiators? That must change the sizing of the heating system, right?

Absolutely correct. The standard heating load or room heating requirements do not change because of this, as they are independent of the heat generator (controlled residential ventilation with or without heat recovery should be considered!). However, the actual energy consumption, heating surfaces, and therefore the pipe hydraulics will be affected. With precise planning, the underfloor heating structure will also change, and if heat recovery is necessary, the wall construction as well! The reliability of the provider can be easily judged if they make no statements about this. This will be significant in more than 99% of general contractor projects. It is no coincidence that savvy builders take this trade out of the contract and assign it separately after exact planning and sizing.

Best regards

P.S.: Saving energy costs begins with selecting the building plot!

Cascada schrieb:
...As often seen in forums, caution is sometimes necessary here because consumption figures are "adjusted" or calculated in ways that are unrealistic in practice.

Correct, since the main goal is essentially to take customers off the market. Almost all sales tactics are used for this purpose.

Cascada schrieb:
...For underfloor heating, the temperature should not exceed 35 degrees Celsius (95°F). Therefore, underfloor heating as a surface heating method is basically a requirement for using a heat pump.

Exactly! Addition: In bathrooms, additional underfloor heating areas or other energy sources are often necessary.