Hot water circulation pump

Hello everyone,

our heating engineer said that he would actually install a circulation pump, but could also omit it. Operating costs would be about 30-50 € per year and every 6 years he guesses it would need to be replaced. We of course don’t want to wait 30 seconds for the first warm water either. He also said that he can reduce the cross-section of the pipes to reduce this somewhat. Does anyone have experience with the pumps – from which pipe length/distance would you recommend one?

Another topic was the ventilation of the utility room, WC and kitchen – here he said you could install a mushroom pipe / mushroom valve / mushroom thing... to avoid ventilation via the roof. Does anyone know this? Does it stink somehow? I can’t imagine that.

Thanks and best regards.

Good morning,

our heating engineer said that he would actually install one, but could also leave it out.

If I remember correctly, you want to build a KFW 70 efficiency house; doesn’t your heating engineer know that? Efficiency house and circulation line are a no-go.

Rhenish greetings

On the topic of circulation, I can tell you that we no longer want to do without it. However, the pump does not run continuously. We have motion sensors in the bathrooms that turn it on (= first to the toilet, then directly warm water for the hands or the shower). In the kitchen, we can operate the pump with a switch, but since the pipeline route is very short, the switch was unnecessary.

KFW55 even... but why is that a no-go? Because the water always cools down in the pipes and the heating constantly has to reheat?

KFW55 even... but why is that a no-go? Because the water always cools down in the pipes and the heating constantly has to reheat?

Yes, because it contradicts the requirements of the Energy Saving Ordinance and would - if installed - endanger your approved subsidy funds. Shortly before handover of the house, the KFW 55 status must be confirmed again based on the delivery notes for the installed materials. No competent inspector would approve that

Rhenish greetings

Uff - thanks for the tip. Just got told in the pink forum that 30 € operating costs for the circulation pump is a gross exaggeration (of course, we still won’t do that - see Epis' comment). For the mushroom valve for the ventilation, it was said that it wouldn't smell, but it makes noise. Alternatively, the ventilation could go through the children's room (not so dramatic - you'd have to wall up a pipe box or something) - but if we could do without it, why not.