DHW in a Passive House

gears

I'm just wondering how DHW is heated through out the year in a passive house. I assume solar panels would be in place so heating water during the summer shouldn't too much trouble but what about during the winter ?
From what little I know of solar to heat water during the winter you would need an array 3 or 4 times larger that for summer, so that's probably not practical. There would not be any boiler in place so that's out. So all I can think of is an immersion heater is this the only solution?

CJhaughey

I would say an immersion or a small air to water heatpump.

Poor Uncle Tom

What would be wrong with having a back-up boiler? It is not likely the average amount of panels alone would keep you in your hot water needs from October to April of any year, imo.

sinnerboy

http://www.mosart.ie/passive-house/back-up-heating.html

gears

Poor Uncle Tom wrote: »

What would be wrong with having a back-up boiler? It is not likely the average amount of panels alone would keep you in your hot water needs from October to April of any year, imo.

There's probably nothing wrong with having a small boiler but I'm just wondering whats conventionally used. Perhaps a stove with back boiler? It would avoid having a boiler plus some from of fuel storage.

sinnerboy wrote: »

http://www.mosart.ie/passive-house/back-up-heating.html

This link doesn't suggest any from of back up heating just says that it will be required......

CJhaughey wrote: »

I would say an immersion or a small air to water heatpump.

Air to water heatpump.. I hadn't thought about this. How small can you get one of these considering they're designed to heat a home?

gears

sinnerboy wrote: »

http://www.mosart.ie/passive-house/back-up-heating.html

Sorry I continued to look around the site and found this

http://www.mosart.ie/passive-house/key-components.html

Where the back up heating system is briefly mentioned. But it is a pellet boiler that is mentioned first which seems an expensive piece of equipment to simply heat DHW.

CJhaughey

gears wrote: »

Air to water heatpump.. I hadn't thought about this. How small can you get one of these considering they're designed to heat a home?

You can get small ones designed specifically designed for heating DHW.
My mate has one in his house and he thinks it works well, he had a few setup problems with running it 24/7 but now has it sorted.

Do-more

gears wrote: »

This link doesn't suggest any from of back up heating just says that it will be required......

Yes it does.

Typically any additional heating required is delivered using the mechanical ventilation system. The air passing around the house can be heated using a variety or combination of means whether electrical-based (such as with a heat pump) or using a pellet-boiler and / or solar panels. It is not usual to find (or indeed need) radiators or underfloor heating in a Passive House. If you really would like such systems, then of course they can be used. Be aware that in doing so, you are ‘doubling up’ the amount of services in your house, which will, in turn, increase the cost of construction.

It's not just providing DHW it's supplementing the space heating also.

gears

CJhaughey wrote: »

You can get small ones designed specifically designed for heating DHW.
My mate has one in his house and he thinks it works well, he had a few setup problems with running it 24/7 but now has it sorted.

Could you post a link or PM one with your friends unit, I 'd be curious to look at some specs. Thanks

morning delight

CJhaughey wrote: »

You can get small ones designed specifically designed for heating DHW.
My mate has one in his house and he thinks it works well, he had a few setup problems with running it 24/7 but now has it sorted.

This thread is a bit old so I hope you get this post! Can you PM me details as well.
Cheers.