New construction in planning, which heating system?

  • Erstellt am 2010-04-27 01:00:12

johnny

2010-04-27 01:00:12
  • #1
Hello everyone,

we are planning to build a semi-detached house soon and are still faced with the question of which heating system!?!?!

We have already been to several construction companies to get offers for our house construction, but all of them suggested something different for the heating.

The groundwater level on our plot is relatively high (2.5m).

The first construction company recommended a groundwater heat pump because of the high groundwater.

The second construction company recommended a normal gas heating system.

And the third company recommended an air-to-water heat pump with a ventilation system (heat recovery).

And our insurance advisor (construction financier), who is also a good friend of ours, said we should do underfloor heating with solar energy. Can you operate underfloor heating with only solar energy, is that sufficient?

Of course, for all offers in combination with underfloor heating, we also want to have a fireplace.

Our house will have 2 floors, plus a basement and about 140sqm without the basement.

I am grateful for any advice!
 

6Richtige

2010-04-27 11:45:44
  • #2
Hello jonny,

all three companies are right, depending on what is important to you: investment costs, operating costs, ecology, and possibly the connected utilities.
You cannot heat a house completely with a solar system.
I would choose the provider who offers a waterproof basement in their offer; the additional costs incurred will also help in selecting the heating system ;)
 

johnny

2010-04-27 13:41:46
  • #3


Ok, they all offered a waterproof basement, but that is also a matter of price. Therefore, we tend towards the first offer, which presents the shell construction with waterproof basement, exterior plaster, and interior plaster for about 60,000,- including insulation. And this one recommended the groundwater heat pump.

The heating system can cost a bit more to purchase; however, we want to keep the monthly consumption costs as low as possible if feasible. What is good for that?
 

6Richtige

2010-04-27 14:08:05
  • #4
Hello johnny,

the most cost-effective in terms of operating costs should be the heat pump for groundwater, then air heat pump, then gas.

Did I understand you correctly that you are calculating with 60,000 € for the shell construction of 210 m2 living/usable space including waterproofed basement and insulation?

Just for the basement with insulation and waterproofing without earthworks I would estimate about 40,000 €, so something is probably missing in the offer, right? How will the basement be executed, white, brown, black or orange waterproofing? Are pump costs during the construction period already included or is the basement ceiling one meter above ground level?
 

€uro

2010-04-27 16:38:59
  • #5
Hello,

This is not surprising at all. If you asked even more, X new variants would appear and the confusion would be complete!
The ultimate and universally valid heating system definitely does not exist! However, there is a particularly advantageous solution for every project. This must be found. The building, orientation, location, climate site, user behavior, etc. form a unit. Also, building services engineering (heating, hot water preparation, ventilation, etc.) must always be considered as a whole.
Without knowledge of your individual framework conditions, no objective recommendation can be given if it is to be meaningful and effective.

Solely the height of the groundwater level alone is not a decision criterion for a groundwater heat pump! Due to the requirements for water quality, there are relatively few sites suitable for the effective use of a groundwater heat pump! Here too, the framework conditions (recharge, absorption wells; iron hydroxide clogging) would first have to be clarified. If the surroundings are correct, very good annual performance factors can be achieved.

That can be an option, but it is not said that this is actually the cheapest option for you. Here, most often estimates and guesses are made rather than calculations, which later proves to be very disadvantageous in operation.

The above also applies here, first the framework conditions must be clarified! Air heat pumps have characteristic curves that oppose the actual demand (building load curve) most strongly! Therefore, they are mostly used bivalently, i.e., with an additional heating element at low outdoor temperatures. This means partial electric heating! Otherwise, they would be mercilessly oversized in main operation, which can lead to considerable problems. In addition, here another component, ventilation, is mentioned, making a real comparison impossible!
It should be clarified beforehand whether a ventilation system is even required/necessary or desired for comfort reasons! With heat recovery, efficiency values are mostly advertised that are rarely achieved in practical operation. Therefore, this investment should also be carefully checked in advance.
Nevertheless, air-to-water heat pumps, despite their lower annual performance factor compared to other heat pumps, can represent a good solution for individual cases, provided sufficient dimensioning! Here the energy expenditure for hot water preparation has a particularly large influence.

Where does the insurance advisor get his knowledge? He certainly does not have training in building services engineering! You don’t go to the baker for toothache!!!

Again, a standard and general statement. Both underfloor heating and radiators or convectors each have advantages and disadvantages. Underfloor heating and radiators are slow, so heating on demand is hardly possible; i.e., heating usually has to be continuous! The fireplace is primarily responsible for the experience of “fire”! Sustainable saving effects in combination with underfloor heating will hardly be possible because it cannot adequately react to the additional heat source. Radiators are much better suited for this. Their quick control behavior allows heating "ad libitum." External heat sources (fireplace) can be used much more effectively. This can result in significant savings effects depending on user behavior and the insulation standard of the building without loss of comfort.
With increasingly well-insulated building envelopes, however, these savings become smaller, so that the difference hardly remains effective. Where the limit lies can be calculated in advance.
With heat pumps as heat generators, underfloor heating is a prerequisite for effective operation. Warm feet in the bathroom are no longer reasonably possible. Additional heating surfaces are often required.
Basically: before signing a contract, sufficient checking and calculation are mandatory. This includes in particular the heating load (DIN 12831) as well as the annual energy demand for heating and hot water! Based on that, the overall concept is developed. The results from the energy saving ordinance verification are generally not suitable for this!!!
Objective and independent advice can only be obtained from a qualified specialist who does not sell, install, or broker!

Best regards
 

johnny

2010-04-27 16:40:57
  • #6
This was the offer from the first construction company.

Approximately 60,000,- for the shell construction, including a waterproof basement, insulation, exterior/interior plaster, without window installation.

Whether brown, white, or some other kind of tub, I have no idea, I don't even know the difference, so far I've only heard of a white tub, but I really don't know what that is.

Whether the earthworks are included, I don't know. The exact offer should still come this week, he only gave a rough estimate and just said what is included (insulation, exterior/interior plaster). He didn't say what is not included and I hope that the catch with the offer won't come later.

Can you tell me the differences between the tubs?
 

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