ᐅ Request for Evaluation of Heating and Ventilation Concept for a New Single-Family House
Created on: 31 Dec 2015 19:32
H
holg182
Hello everyone,
We are planning to build a detached single-family house, about 160 sqm (1,722 sq ft), on an 1100 sqm (11,840 sq ft) plot at the edge of town with a slight slope on slate soil. We are aiming for approximately a KfW 70 energy efficiency level, although with the current interest rates we are not relying on the related subsidies. Overall, our planning is going quite well, but when it comes to heating and ventilation, we are unsure if our plan really makes sense. Therefore, we appreciate your opinions on this 🙂
In general, we want to build and operate the house simply and cost-effectively, and it would be great if we could do this with a clear conscience for the environment. Our idea:
- A fairly well-insulated building envelope (see above), without it becoming a bottomless pit.
- Air-to-water heat pump
- Pellet stove in the living room
- Controlled mechanical ventilation (with heat recovery)
- Underfloor heating
The idea is that the air-to-water heat pump supplies most of the heat for the house, and the pellet stove in the living room provides extra support when it gets very cold outside. Ideally, this would happen automatically—so that the pellet stove switches on as soon as the outside temperature drops to a certain value, e.g., -3°C (27°F).
Here are a few questions for you experts:
1. Does this concept make sense as a whole?
2. Or would it be better / simpler / more cost-effective overall to use gas for purchase, operation, and maintenance?
3. Should the pellet stove in our setup be water-bearing (hydronic) or not?
4. Should the controlled mechanical ventilation system include heat recovery, or is that not necessarily required? Does a central or decentralized system make more sense here?
5. How can I find someone who can plan, recommend, offer, and install the right equipment for this setup (and not just the products that provide them with the highest commission)?
Thank you very much for your opinions—and Happy New Year in advance 🙂
We are planning to build a detached single-family house, about 160 sqm (1,722 sq ft), on an 1100 sqm (11,840 sq ft) plot at the edge of town with a slight slope on slate soil. We are aiming for approximately a KfW 70 energy efficiency level, although with the current interest rates we are not relying on the related subsidies. Overall, our planning is going quite well, but when it comes to heating and ventilation, we are unsure if our plan really makes sense. Therefore, we appreciate your opinions on this 🙂
In general, we want to build and operate the house simply and cost-effectively, and it would be great if we could do this with a clear conscience for the environment. Our idea:
- A fairly well-insulated building envelope (see above), without it becoming a bottomless pit.
- Air-to-water heat pump
- Pellet stove in the living room
- Controlled mechanical ventilation (with heat recovery)
- Underfloor heating
The idea is that the air-to-water heat pump supplies most of the heat for the house, and the pellet stove in the living room provides extra support when it gets very cold outside. Ideally, this would happen automatically—so that the pellet stove switches on as soon as the outside temperature drops to a certain value, e.g., -3°C (27°F).
Here are a few questions for you experts:
1. Does this concept make sense as a whole?
2. Or would it be better / simpler / more cost-effective overall to use gas for purchase, operation, and maintenance?
3. Should the pellet stove in our setup be water-bearing (hydronic) or not?
4. Should the controlled mechanical ventilation system include heat recovery, or is that not necessarily required? Does a central or decentralized system make more sense here?
5. How can I find someone who can plan, recommend, offer, and install the right equipment for this setup (and not just the products that provide them with the highest commission)?
Thank you very much for your opinions—and Happy New Year in advance 🙂
holg182 schrieb:
Regarding the additional pellet stove in the living room: it's partly a "luxury," we like having a stove, but a wood stove is too much work and mess, so we chose pellet. And I thought, if it's going to be a luxury, at least make it somewhat practical – meaning it should (with or without water circulation?) help ease the heat pump on cold days.
Does that not make sense?Hello again,
if you are basically open to having a pellet stove in the living area, why not give up other heat sources?
If you lived close by, you could come and see one at my place.
Olli
What are you trying to tell us, saboj?
That a tent became a passive house years ago with a pellet heating system?
That switching to bagged pellets reduces heat loss?
That a pellet stove replaces a mechanical ventilation system with heat recovery?
That the heating demand decreases with a pellet heating system?
I just can't seem to follow.
Olli
That a tent became a passive house years ago with a pellet heating system?
That switching to bagged pellets reduces heat loss?
That a pellet stove replaces a mechanical ventilation system with heat recovery?
That the heating demand decreases with a pellet heating system?
I just can't seem to follow.
Olli
wrobel schrieb:
Hello again,
if you can generally get along with a pellet stove in the living area, why not skip other heat generators?
If you lived around the corner, you could take a look at something like that at my place.
OlliGood point, wrobel! Would something like the MZC Vivo 80 Hydro be sufficient for a single-family house?
Hello Holger,
Yes, that should definitely be sufficient. However, I haven’t installed this product yet.
One thing to keep in mind is that the unit is placed in the living area. You can’t really avoid the exhaust fan and the feed screw, and a blower for air distribution also creates additional noise, which I would try to avoid.
Take a look at the PE nova from Wodtke. I’ve been using it for 13 years, and it will also serve as the heating system in the new house.
Olli
Yes, that should definitely be sufficient. However, I haven’t installed this product yet.
One thing to keep in mind is that the unit is placed in the living area. You can’t really avoid the exhaust fan and the feed screw, and a blower for air distribution also creates additional noise, which I would try to avoid.
Take a look at the PE nova from Wodtke. I’ve been using it for 13 years, and it will also serve as the heating system in the new house.
Olli
holg182 schrieb:
Or is it generally better / simpler / cheaper to use gas for purchase, operation, and maintenance? Heat pump tariff for us: 19.91 cents; gas tariff: 5.77 cents. Fixed fees are comparable in both cases. With an annual performance factor of 3.5, the air-to-water heat pump doesn’t save anything compared to gas. Also consider the inspection requirements under EU Directive 517/2014 for the air-to-water heat pump, or, if the desired heat pump is currently not subject to this inspection duty, please estimate yourself whether this might change in the future. In comparison, the chimney sweep every two years is trivial.
Another interesting point occasionally mentioned by Prof. Leukefeld: heat pumps mainly consume electricity when it is expensive (many users in winter, and as more heat pumps are installed, this consumption will increase). The trend is moving towards “smart” electricity meters, and anyone who puts two and two together should soon expect that winter electricity will become more expensive than summer electricity.
Additionally, there are possible hygiene issues (the air-to-water heat pump will hardly be able to heat the hot water tank to 60 degrees Celsius (140°F)), which can be compensated for by further costly systems (hygiene hot water tanks), as well as potential problems with noise, neighbors, and the appearance.
Gas: About 50 percent of Germans use gas for heating. An affordable gas price is therefore politically very significant, and the amount of gas you use in a new building can heat 1–2 rooms in other homes. The market price of gas is currently dropping sharply, and not all recent price reductions have even been passed on yet. Secondly, there are numerous ways to produce gas alternatively, such as so-called wind gas, biogas from plants, or biogas from manure. At the moment, gas is even the only conceivable seasonal energy storage for the energy transition. Given the renewal rate of existing buildings and the fact that even then it is not simple to switch to alternative heating systems, gas will remain the dominant heating method for the coming decades.
P
Peanuts745 Jan 2016 08:23Grym schrieb:
Heat pump tariff for us: 19.91 cents; gas tariff: 5.77 cents. Basic fees are comparable. With an annual performance factor of 3.5, the air-to-water heat pump actually doesn’t save anything compared to gas. For air-to-water heat pumps, also consider the inspection obligations under EU Directive 517/2014, or if the currently desired heat pump is NOT yet covered by this inspection requirement, please assess yourself whether this might change in the future. In contrast, the chimney sweep every two years is a minor matter.
Another interesting topic that Prof. Leukefeld has occasionally mentioned: heat pumps consume electricity mainly when it is expensive (many users in winter, and more heat pumps will further increase consumption). The trend is toward "smart" electricity meters, and those who connect the dots should expect that winter electricity will eventually become more expensive than summer electricity.
Then there are potential hygiene issues (air-to-water heat pumps will hardly be able to keep the hot water tank at 60°C (140°F)), which can be compensated by additional costly equipment (hygiene hot water tanks), as well as possible problems with noise and neighbors, and the aesthetics.
Gas: Used by about 50 percent of all Germans for heating, affordable gas prices are therefore politically very important. The amount of gas you consume in a new building is enough to heat just 1-2 rooms elsewhere. The market price for gas is currently falling sharply, and not all recent price reductions have been passed on yet. Furthermore, there are numerous ways to produce gas alternatively, whether so-called wind gas, biogas from plants, or biogas from manure. At the moment, gas is even the only conceivable seasonal storage option for the energy transition. Given the renewal rates in existing buildings and the fact that switching to alternative heat sources is not simple even then, gas will remain the dominant heating method for the next decades.Especially when you bring up political (intended) aspects, one could also say that if the government needs money, it can quickly impose some kind of tax on gas. Since this tax would be shared by 50% of households, it only results in a small increase for each and would be accepted by the average German without much complaint.
Basically, almost every (modern) heating method costs about the same. Almost everyone who has recently built here pays, regardless of the heating system, around €800 - 1000 per year, whether gas plus solar, pellets (although you need storage space for pellets), or heat pump. Differences arise mostly from heating and ventilation behavior and the building envelope itself.
Whether you pay €3.80 less per month with pellets than with gas, or €1.20 more than with a heat pump, realistically speaking, this hardly plays a role. Every well-designed and professionally installed heating system is efficient these days. By comparison, even houses from the 1990s, which can still be considered quite new, consume about twice as much energy, and here people debate differences of maybe 10, at most 20%.
For me, gas and heat pumps are currently the favorites. If you really want a fireplace, gas is better; otherwise, you can save the gas connection and chimney flue and rather go for the heat pump. Regarding aesthetics, there are also devices that can be installed indoors, or simply place the outdoor unit somewhere unobtrusive.
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