ᐅ District Heating KfW55 - KfW70 Costs for Ventilation and Exhaust Systems
Created on: 1 Sep 2017 21:35
Z
zizzi
Hello everyone,
we are planning a bungalow.
We initially decided on KfW 70 because the payback period for KfW 55 is relatively long (the equipment that needs to be installed requires maintenance, can break down, and partly also consumes electricity). The highway is approximately 500 m (550 yards) from the property and despite a noise protection forest, it is still quite loud. Therefore, we want to plan a ventilation system, probably without heat recovery (ventilation with closed windows).
Today I found out that the property where we want to build is supplied with district heating.
The costs are as follows: one-time fee €9,500, annual basic price for 2017 calculated at €450 (subject to change), energy costs at 5.2 Ct./kWh (subject to change). The formulas for price adjustments are included in the contract (not yet signed) but they are not easily understandable for everyone.
There is an advantage here: the primary energy factor is 0.43 (certified and valid until 2024). According to the energy supplier (municipal utility), the representative told me that KfW 55 standards can only be met with additional thermal insulation compared to KfW 70 (without further measures).
What are your opinions on the resulting maintenance costs, experiences with district heating, and KfW 70 versus KfW 55?
we are planning a bungalow.
We initially decided on KfW 70 because the payback period for KfW 55 is relatively long (the equipment that needs to be installed requires maintenance, can break down, and partly also consumes electricity). The highway is approximately 500 m (550 yards) from the property and despite a noise protection forest, it is still quite loud. Therefore, we want to plan a ventilation system, probably without heat recovery (ventilation with closed windows).
Today I found out that the property where we want to build is supplied with district heating.
The costs are as follows: one-time fee €9,500, annual basic price for 2017 calculated at €450 (subject to change), energy costs at 5.2 Ct./kWh (subject to change). The formulas for price adjustments are included in the contract (not yet signed) but they are not easily understandable for everyone.
There is an advantage here: the primary energy factor is 0.43 (certified and valid until 2024). According to the energy supplier (municipal utility), the representative told me that KfW 55 standards can only be met with additional thermal insulation compared to KfW 70 (without further measures).
What are your opinions on the resulting maintenance costs, experiences with district heating, and KfW 70 versus KfW 55?
Unfortunately, with KfW55 it’s not really the materials that are expensive, but the name and what the general contractor charges for it. Triple-glazed windows, slightly thicker ceiling insulation, and facade insulation practically cost nothing extra since those tasks are going to be done anyway. That’s why it can still be worth considering separate contracts or doing some work yourself.
If you choose a central mechanical ventilation system, I would also recommend one with heat recovery. Otherwise, cold outside air will be distributed everywhere, potentially negating the only financial benefit of mechanical ventilation.
If you choose a central mechanical ventilation system, I would also recommend one with heat recovery. Otherwise, cold outside air will be distributed everywhere, potentially negating the only financial benefit of mechanical ventilation.
zizzi schrieb:
I don’t have much experience in this area, but I believe that to operate a ventilation system with heat recovery, the ducts need to be installed. Aside from the costs involved, I’m concerned that after 5 or 10 years, mold and bacteria could develop inside the ducts that can never be completely cleaned.This is not an air conditioning system, so where would the mold and bacteria come from?
There are two options for controlled residential ventilation with heat recovery: decentralized and centralized systems.
With decentralized systems, a fan with heat recovery function must be installed in each individual room. Many people report that it can become too noisy.
With centralized systems, ducts for extracting and supplying air need to be installed. It is often criticized that after several years, microbial growth can develop in the ducts, and it can never be cleaned as thoroughly as before. I don’t know the exact costs, but I estimate it could be over €10,000, and I wonder when such an investment pays off. Since it requires maintenance, and considering the possibility of breakdowns, is that not correct?
I will still discuss with our builder, but my plan is as follows: stale air will be extracted from the kitchen, bathroom, and utility room (using a fan powered by electricity or wind-driven), while fresh air will come into the bedrooms and living room through valves with filters and sound insulation. The system should operate when CO2 or humidity levels are too high. The valves will allow less air flow when there is a large temperature difference between inside and outside.
What do you think?
With decentralized systems, a fan with heat recovery function must be installed in each individual room. Many people report that it can become too noisy.
With centralized systems, ducts for extracting and supplying air need to be installed. It is often criticized that after several years, microbial growth can develop in the ducts, and it can never be cleaned as thoroughly as before. I don’t know the exact costs, but I estimate it could be over €10,000, and I wonder when such an investment pays off. Since it requires maintenance, and considering the possibility of breakdowns, is that not correct?
I will still discuss with our builder, but my plan is as follows: stale air will be extracted from the kitchen, bathroom, and utility room (using a fan powered by electricity or wind-driven), while fresh air will come into the bedrooms and living room through valves with filters and sound insulation. The system should operate when CO2 or humidity levels are too high. The valves will allow less air flow when there is a large temperature difference between inside and outside.
What do you think?
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