ᐅ Heating screed with a heating device versus a heat pump – costs?
Created on: 14 Sep 2022 22:04
S
Sandra.M85
Hello,
Two weeks ago, the screed (cement screed) was poured in our new single-family home (about 130 sqm (1400 sq ft) floor area).
Our general contractor (GC) now offers us the following options:
1) Heating the screed using a 19 kW heating device, starting in 10 days.
2) Heating the screed via underfloor heating powered by a heat pump after the heat pump is installed in mid-October.
According to our contract, I am responsible for paying the heating costs, while the GC covers construction electricity. The house completion date is set for February 2023 in the contract.
Option 1: The GC says I must pay for the construction electricity used by the heating device because it counts as heating costs. Until now, I assumed that heating costs cover the energy needed to keep the workers working, but not the energy used specifically to heat the screed. If I prefer option 1, I understand that I will have to cover these costs, but the GC will still complete the house by February using the cheaper option 2.
How expensive would option 1 be? What is the cost of construction electricity, and how much electricity is needed to operate the heating device until the screed is dry?
According to the GC, option 1 would allow me to move in this year, which could save me about one month’s rent for my current apartment—around 650 euros—and avoid the risk that the heat pump might not be installed by mid-October, as required for option 2.
Option 2: After the heat pump is installed in mid-October, if the screed is heated via underfloor heating, does the GC cover the electricity used for this? Would this electricity still be measured by the construction electricity meter (paid by the GC according to the contract), or would it already be charged through my new private electricity meter?
How much electricity would be needed to heat the screed this way, and if I had to pay for this electricity, approximately how much cheaper would option 2 be compared to option 1?
Which option would you choose?
Two weeks ago, the screed (cement screed) was poured in our new single-family home (about 130 sqm (1400 sq ft) floor area).
Our general contractor (GC) now offers us the following options:
1) Heating the screed using a 19 kW heating device, starting in 10 days.
2) Heating the screed via underfloor heating powered by a heat pump after the heat pump is installed in mid-October.
According to our contract, I am responsible for paying the heating costs, while the GC covers construction electricity. The house completion date is set for February 2023 in the contract.
Option 1: The GC says I must pay for the construction electricity used by the heating device because it counts as heating costs. Until now, I assumed that heating costs cover the energy needed to keep the workers working, but not the energy used specifically to heat the screed. If I prefer option 1, I understand that I will have to cover these costs, but the GC will still complete the house by February using the cheaper option 2.
How expensive would option 1 be? What is the cost of construction electricity, and how much electricity is needed to operate the heating device until the screed is dry?
According to the GC, option 1 would allow me to move in this year, which could save me about one month’s rent for my current apartment—around 650 euros—and avoid the risk that the heat pump might not be installed by mid-October, as required for option 2.
Option 2: After the heat pump is installed in mid-October, if the screed is heated via underfloor heating, does the GC cover the electricity used for this? Would this electricity still be measured by the construction electricity meter (paid by the GC according to the contract), or would it already be charged through my new private electricity meter?
How much electricity would be needed to heat the screed this way, and if I had to pay for this electricity, approximately how much cheaper would option 2 be compared to option 1?
Which option would you choose?
S
Sandra.M8515 Sep 2022 13:51WilderSueden schrieb:
. The estimated demand given to me was between 1000 and 2500 kWh, also highly dependent on the weather. For my project, a demand of about 6300 kWh was stated—where does this large difference come from?
W
WilderSueden15 Sep 2022 14:15How high is the screed heated in your case? We had quite a big discussion here about whether it’s really necessary to heat the screed above 50°C (122°F) when in practice the supply temperature is only around 30°C (86°F). I suspect this might be where the difference lies. However, I’m not sure myself since I don’t know our planned heating schedule yet.
By the way, the calculation above is just a rough estimate assuming continuous full load at 19 kW. Since the temperature is gradually increased and decreased, I wouldn’t expect full load to be permanent.
edit:
I quickly searched and found a rule of thumb of 20 kWh per sqm. That would be about 2600 kWh for 130 sqm (1400 sq ft). Can someone confirm this who has already heated their screed?
By the way, the calculation above is just a rough estimate assuming continuous full load at 19 kW. Since the temperature is gradually increased and decreased, I wouldn’t expect full load to be permanent.
edit:
I quickly searched and found a rule of thumb of 20 kWh per sqm. That would be about 2600 kWh for 130 sqm (1400 sq ft). Can someone confirm this who has already heated their screed?
WilderSueden schrieb:
How high do you heat your screed? We once had a lengthy discussion here about whether it’s really necessary to heat the screed above 50°C (122°F) when in practice the flow temperature is only around 30°C (86°F). I suspect this might be where the difference lies. However, I’m not sure myself since I don’t yet know our planned heating schedule.
By the way, the calculation above is a rough estimate based on continuous full load at 19 kW. Since the temperature is gradually increased and decreased, I wouldn’t assume constant full load.
edit:
I quickly looked it up and found a rule of thumb of 20 kWh per sqm (square meter). That would be about 2600 kWh for 130 sqm (1400 sq ft). Can anyone confirm this from experience with heated screed?In our new office, the landlord mentioned a heating temperature of 50°C (122°F). I think it’s also about (or exactly about) relieving stress from the screed...W
WilderSueden15 Sep 2022 16:19Yes, exactly, it’s about the stresses. However, I recall a longer thread discussing whether 50 degrees Celsius (122°F) is really necessary if the heating system is designed for a supply temperature of 28-30 degrees Celsius (82-86°F). Since the temperature is always adjusted in small increments, a 20-degree difference (36°F) ends up lasting a few days longer, specifically the hottest ones.
I can't quickly find the thread.
I can't quickly find the thread.
S
SaniererNRW12316 Sep 2022 08:31i_b_n_a_n schrieb:
In our new office, the landlord mentioned a 50° heating temperature. I think it’s about relieving stress in the screed... Yes. There are two different types of heating:
1. Functional heating
2. Drying heating / readiness heating
It’s easier than explaining it myself:
Although functional heating is often still specified at around +/- 50 degrees Celsius (122°F), it is now common not to go that high, since the maximum supply temperature is usually limited to 30 degrees Celsius (86°F), and the full 50 degrees Celsius (122°F) difference is no longer necessary.
The screed installer decides the duration and temperature of the heating.
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