ᐅ Underfloor Heating and Air-to-Water Heat Pump in New Construction: Am I Inviting Problems?
Created on: 16 Jul 2021 18:03
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neo-sciliar
Hello everyone,
I have posted here several times before and have received a lot of really helpful advice. I have learned a lot. But reality is catching up with me: we are currently building a new house, and because of the builder, we are tied to a specific heating installer (alternatively, we could choose our own, but then we would have to find all the other tradespeople ourselves, including electrical, plumbing, and everything that follows). Since this is already contractually agreed, the matter is settled.
In my opinion, based on what I have learned here, he is doing everything "wrong":
1.) Viessmann air-to-water heat pump Vitocal 222-S with 7.2 kW, although the calculation shows only 5.5 kW needed
2.) Buffer tank to enable flow rate and prevent short cycling
3.) ERRs (electronic room regulators) in the main rooms (he wanted ERRs in all rooms, I limited it to the important ones)
4.) I saw on site today: heating circuits of varying lengths—from 30 m (98 feet) up to 120 m (394 feet). At least the spacing of the underfloor heating pipes is adjusted according to the room requirements, from 5 cm (2 inches) in the bathroom to 30 cm (12 inches) in the bedroom
Now my questions: Am I setting myself up for real problems, or is all this actually irrelevant (as he claims) and the system will still run properly? By properly I mean that a) it heats well and b) electricity consumption stays within reasonable limits (seasonal performance factor > 4.5, calculated at 4.9).
Best regards, Andreas
I have posted here several times before and have received a lot of really helpful advice. I have learned a lot. But reality is catching up with me: we are currently building a new house, and because of the builder, we are tied to a specific heating installer (alternatively, we could choose our own, but then we would have to find all the other tradespeople ourselves, including electrical, plumbing, and everything that follows). Since this is already contractually agreed, the matter is settled.
In my opinion, based on what I have learned here, he is doing everything "wrong":
1.) Viessmann air-to-water heat pump Vitocal 222-S with 7.2 kW, although the calculation shows only 5.5 kW needed
2.) Buffer tank to enable flow rate and prevent short cycling
3.) ERRs (electronic room regulators) in the main rooms (he wanted ERRs in all rooms, I limited it to the important ones)
4.) I saw on site today: heating circuits of varying lengths—from 30 m (98 feet) up to 120 m (394 feet). At least the spacing of the underfloor heating pipes is adjusted according to the room requirements, from 5 cm (2 inches) in the bathroom to 30 cm (12 inches) in the bedroom
Now my questions: Am I setting myself up for real problems, or is all this actually irrelevant (as he claims) and the system will still run properly? By properly I mean that a) it heats well and b) electricity consumption stays within reasonable limits (seasonal performance factor > 4.5, calculated at 4.9).
Best regards, Andreas
R
RotorMotor17 Jul 2021 11:31More theory has been added again. Unfortunately, there is no information on how much pump energy, etc., is actually saved. Practical solutions for equipping a small room with a long loop are still missing. The often recommended "wall heating," for which the contractor quickly charges 1000€ (around $1100), also raises doubts about whether all this theory makes sense in practice.
RotorMotor schrieb:
A lot more theory has been added again. Unfortunately, there is no information on how much pump current, etc., is actually saved. Practical solutions for equipping a small room with a long circuit are still missing. Just like the often recommended "wall heating," for which the installer quickly charges around €1000, making one question whether all that theory still makes sense in practice.Since no one knows the system design, no one can calculate anything… no arms, no legs, no cookies 😉, but as the additional costs tend toward zero or can even be negative, this becomes irrelevant. Small rooms can be combined. Since the “ancillary rooms” are supposed to run unregulated anyway, it makes no difference. Supply goes to the desired warmer room, return to the “cold” one.
If the goal is to keep it cheap, build according to the energy saving regulations with a gas boiler.
If you only look at individual parts, you might reach questionable conclusions, which is why I prefer overall comparisons:
Eliminated:
- Buffer tank
- Second pump group
- Thermostats
- Return temperature regulators (RTR)
- Any actuators
- Wiring
Neutral to about 2 hours more effort:
- Planning
Additional costs (optional, if aiming for efficiency, but neither is mentioned here):
- Wall heating
- A few hundred meters more pipe
You can add prices yourself, as you seem to have the necessary knowledge 😉
We will not consider efficiency through lowering the supply temperature for simplicity, as that is just theoretical again. The rest are simple side effects using the same resources with cost savings through less material.
The original poster is aware they will have to accept what is offered, so this is purely a theoretical exercise anyway…
One last tip: ask how many electricity meters will be installed. Often, a second meter is not worthwhile in a single-family house due to additional basic fees.
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nordanney17 Jul 2021 22:31Joedreck schrieb:
Request a room-by-room heat load calculation, then have the underfloor heating designed with similarly sized heating circuits.Even professionals don’t design everything with identical lengths. So, experienced installers also have both shorter and longer circuits. Ask Heckmann, who is frequently mentioned online. Once again: this is generally not a problem.I fully agree with everything else (also with @borxx). For example, the design should have ideally been 30/26.
nordanney schrieb:
Even professionals don’t interpret everything the same way right away. Even experts sometimes have both short and longer cycles. Just ask Heckmann, who is often mentioned online. Once again: this is generally not a problem.
I fully agree with everything else (also @borxx). For example, the planning should have been 30/26.I said something similar—not right away...N
nordanney17 Jul 2021 23:20Joedreck schrieb:
I said something similar, not exactly the same...But I also mean distances like 40m (130 feet) or 120m (390 feet).Similar topics