Hello everyone,
I’m somewhat heat-sensitive. Until now, I have always lived in apartments that would get extremely hot in summer, despite maximizing shading during the day and ventilating strongly with rapid air exchange at night. Those were the days of my childhood spent in a basement apartment, where even in the height of summer the bedroom stayed pleasantly cool.
To get to the point: I definitely don’t want to deal with that in my own home. So, air conditioning is an important topic for me. My question is: what is the best way to maintain comfortable temperatures even in the peak of summer?
I have read that heat pumps can also provide cooling through underfloor heating, although the effect seems to be relatively mild. It’s also said that mechanical ventilation with heat recovery can be combined with cooling, but here, too, there are obviously fairly strict limitations. Finally, there is the conventional split air conditioning system, which certainly cools well but also consumes a lot of electricity. However, combined with solar panels on the roof, electricity costs should remain manageable since there is usually a surplus of electricity in summer that’s hard to use otherwise.
What would you recommend considering both cost and comfort? Maybe some combination makes sense, for example cooling with a heat pump via underfloor heating and additional cooling through mechanical ventilation with heat recovery – perhaps a moderate amount of cooling from two systems is sufficient in combination. Who has experience and can share knowledge and opinions?
Best regards,
HB1
I’m somewhat heat-sensitive. Until now, I have always lived in apartments that would get extremely hot in summer, despite maximizing shading during the day and ventilating strongly with rapid air exchange at night. Those were the days of my childhood spent in a basement apartment, where even in the height of summer the bedroom stayed pleasantly cool.
To get to the point: I definitely don’t want to deal with that in my own home. So, air conditioning is an important topic for me. My question is: what is the best way to maintain comfortable temperatures even in the peak of summer?
I have read that heat pumps can also provide cooling through underfloor heating, although the effect seems to be relatively mild. It’s also said that mechanical ventilation with heat recovery can be combined with cooling, but here, too, there are obviously fairly strict limitations. Finally, there is the conventional split air conditioning system, which certainly cools well but also consumes a lot of electricity. However, combined with solar panels on the roof, electricity costs should remain manageable since there is usually a surplus of electricity in summer that’s hard to use otherwise.
What would you recommend considering both cost and comfort? Maybe some combination makes sense, for example cooling with a heat pump via underfloor heating and additional cooling through mechanical ventilation with heat recovery – perhaps a moderate amount of cooling from two systems is sufficient in combination. Who has experience and can share knowledge and opinions?
Best regards,
HB1
H
Hausbauer15 Jul 2017 13:39Boergi schrieb:
What exactly do you want to know?
Our house is a new build from 2013, with 42.5cm (17 inches) Poroton masonry filled with perlite, a gable roof with a 22° pitch, tiles, and standard insulation between the rafters.
The heat pump is a Vaillant geotherm VWS 63/3, operated with two boreholes each 85m (279 feet) deep. As I mentioned, the extra cost for the version with cooling function was about 700€. No other measures were taken.
The supply temperature on hot days is around 20°C (68°F). I think 17-18°C (63-64°F) would also be fine, but 20°C (68°F) is more than enough for us.
On hot days, we keep the shutters on the upper floor about two-thirds closed; the blinds on the ground floor are tilted open just a bit. Over the past weeks, the indoor temperature only once reached 24°C (75°F), and 90% of the time it stayed below 23°C (73°F).Okay, so you have a brine-to-water heat pump with two ground probes. I assume that this system fully covers your heating (underfloor heating) and domestic hot water? Or are there additional system components? Can you share anything about the purchase cost and operating costs?
You also mentioned that the mechanical ventilation with heat recovery system provides cooling as well. Is a separate heat exchanger used for this, or is it integrated with the brine-to-water system? What are the conditions for the ventilation? What temperature does the air have when it comes out? Purchase cost? Running costs?
Honestly, your system would be my top choice if the cooling capacity is really adequate. Otherwise, we would probably end up with air conditioning, possibly combined with solar panels on the roof, which would significantly reduce running costs.
Do you have shutters or blinds on all your windows? What is the orientation of the house? For example, many windows facing south? Is there any natural shading? Large trees or shadows from bigger buildings that fall on the house? Do you have an attic space directly under the roof, and if so, how are the temperatures there?
Oh, and how was the coordination between the heat pump with cooling function and the ventilation system with cooling function managed?
Sorry for so many questions. But I find your setup very interesting.
Hausbauer1 schrieb:
So, you have a brine-to-water heat pump with two ground probes. I assume it handles both the heating (underfloor) and domestic hot water completely. Or are there other system components? Could you share some information about the initial investment and running costs? Exactly, a compact unit with an integrated hot water tank.
I deliberately kept the system as simple as possible, without a buffer tank, mixing valves, or demand-controlled ventilation (ERR). However, the preparations for those are already in place in the rooms and distribution units.
The heat pump cost 8,000€ plus installation, and the deep drilling including all piping, shaft, and expert fees was 13,000€. Unfortunately, prices are quite high in our area. The ongoing costs consist only of electricity consumption, which has been between 3,100 and 3,500 kWh annually in recent years for 185 sqm (2,000 sq ft) of heated living space, including domestic hot water. We also have a small photovoltaic system on the roof that covers part of this consumption.
You also mentioned that your controlled mechanical ventilation (CMV) system provides cooling. Is there an additional heat exchanger involved, or is it connected to the brine-to-water system? What are the operating conditions of the CMV? What is the supply air temperature? Initial costs? Running costs? The CMV has its own brine ground heat exchanger consisting of a 100-meter (330 feet) brine pipe laid around the house during the basement backfilling, a pump, and a heat exchanger.
Initial cost was about 2,000€.
Energy consumption of the ground heat exchanger: 242 kWh per year
Energy consumption of the CMV system: 570 kWh
At an outdoor temperature of 30°C (86°F), the supply air temperature is about 20°C (68°F).
Honestly, your system would be my favorite if the cooling capacity is really sufficient. Otherwise, we’d likely revert to an air conditioning unit, possibly combined with solar panels on the roof, which significantly reduce running costs. If you’re planning a heat pump anyway, you can test it without much financial risk. If the cooling capacity isn’t sufficient, you can always retrofit an air conditioner later.
Do you have roller shutters or venetian blinds on all windows? What is the house orientation? For example, many windows facing south? Is there any natural shading, like large trees or shadow from nearby buildings? Do you have a full attic directly under the roof, and if so, how are the temperatures up there?
[QUOTE]
There is shading on all east, south, and west-facing windows. There is no natural external shading (detached single-family house in a new development area).
Attached is a photo from the construction phase; the street side with the bay window faces south. There is no full attic; the rooms on the upper floor have relatively high knee walls (just under 2 meters (6.5 feet)). The sloped ceilings and ceiling are directly insulated, while the small attic storage space is not insulated. Temperatures on the upper floor are generally similar to the ground floor, around 23°C (73°F). My wife even sleeps in long pajamas when it’s 30°C (86°F) outside.
[QUOTE]
Oh, and how is the coordination between the heat pump with cooling function and the CMV system with cooling function handled? There is no direct coordination. The heat pump operates based on outdoor temperature and activates cooling above a certain average temperature. The ground heat exchanger for the CMV system switches on and off depending on set maximum and minimum temperature thresholds.
Sorry for all the questions, but I find the solution very interesting. Feel free to ask anytime. [/QUOTE][/QUOTE]
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Steffen806 Jul 2017 10:09merlin83 schrieb:
I would simply choose the method for which the installer guarantees that even at 40°C (104°F) room temperature and 40°C (104°F) outside temperature, the room cools down to a comfortable 22°C (72°F) within one hour.Exactly. And that is only possible with a traditional air conditioning system. Period!
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bierkuh836 Jul 2017 10:17merlin83 schrieb:
I would simply choose the method for which the installer guarantees, even at 40°C (104°F) room temperature and 40°C (104°F) outside temperature, that the room will cool down to a comfortable 22°C (72°F) within an hour.And when would such a scenario ever occur? Why would anyone oversize a system like that? We still live in Germany, not in the desert.
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Steffen806 Jul 2017 10:36bierkuh83 schrieb:
And when would this situation ever occur? Why would anyone oversize a system like that? We still live in Germany, not in the desert.Of course, it's unlikely... but we have already had 38°C (100°F) over a longer period. And in the coming years and decades, it probably won’t get any cooler.
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