Passive house - back up heating?

jimmy_t

What is the most cost effective way to supply back up heating to a passive house?

fclauson uses UFH with A2W pump
MosArts Out of the blue has radiators on the north of the house fueled by a pellet stove

for the amount of heating required, estimated at a max of 3.5kW by fclauson, can this be provided for a lower capital expenditure, for example a 3.5kW biofuel fire or a direct air heating system integrated into MHRV?

Any thoughts?

Calahonda52

There are electric coils that can be fitted in the MHRV duct, no idea of price

jimmy_t

I think it would be fair to assume that would be cheaper than installing an UFH system though?

jimmy_t

After some googling i found "exhaust air heat pumps" these claim to provide 2-3kw to the home, which, if supplemented with a sealed stove or biofuel fire could be the capital investment sweet spot for heating a passive home. Anyone any experience with an exhaust air heat pump?

BryanF

What do you mean by backup?
How are you heating your water?
Have you done your phpp calc?
3.5wh (h/m2?) how is you arch/eng proposing you comply with part L / BER?

sydthebeat

jimmy_t wrote: »

After some googling i found "exhaust air heat pumps" these claim to provide 2-3kw to the home, which, if supplemented with a sealed stove or biofuel fire could be the capital investment sweet spot for heating a passive home. Anyone any experience with an exhaust air heat pump?

why would a stove or biofuel fuel need a back up? surely THEY are the back up ?

jimmy_t

What do you mean by backup?

All i mean is a passive house theoretically should be getting the its heating from passive solar, but from practical examples available they also need an additional space heating source

How are you heating your water?

The exhaust air heat pump i found claims to provide DHW also

Have you done your phpp calc?

No architect will do that down the line

3.5wh (h/m2?) how is you arch/eng proposing you comply with part L / BER?

I havent gone through it with him in any detail, very early stages at the moment but a brief conversation about heating and he mentioning A2W with some UFH and Solar.

why would a stove or biofuel fuel need a back up? surely THEY are the back up ?

Good point, i mentioned them just because the exhaust air heat pump was only claiming 2-3kW which was below what fclauson determined his max load was at 3.5kW. But its a good point and what i was looking for, maybe we could just put in a stove and that would be enough? I would love to see a practical example of a more minimal heating setup

ht9zni1gs28crp

jimmy_t wrote: »

Have you done your phpp calc?

No architect will do that down the line

Pointless question and pointless worrying until the PHPP has actually been reached and ready for discussion.....

Not being smart but your house design may mean it achieves perfect gain or it struggles to fill the demand. An A2W setup will suit a light requirement but if your filling a large demand then a different option may be required.

Then and only then can you do cost comparisons that work for YOU, these may or may not work for others....

jimmy_t

Nikolas Petite Quirk wrote: »

Pointless question and pointless worrying until the PHPP has actually been reached and ready for discussion.....

Not being smart but your house design may mean it achieves perfect gain or it struggles to fill the demand. An A2W setup will suit a light requirement but if your filling a large demand then a different option may be required.

Then and only then can you do cost comparisons that work for YOU, these may or may not work for others....

Yes, after some further research this became more obvious, I need to work out the heat demand before I could possibly define the heat source. I have seen some interesting options in my research including IR heaters in the carrigaline passive house and duct heaters by Nilan but as stated ill return to this after the PHPP calcs

ht9zni1gs28crp

jimmy_t wrote: »

Yes, after some further research this became more obvious, I need to work out the heat demand before I could possibly define the heat demand. I have seen some interesting options in my research including IR heaters in the carrigaline passive house and duct heaters by Nilan but as stated ill return to this after the PHPP calcs

A good house design with solar gain and solar shading in mind will surprise you on how efficient and less its demands are for external source of heat...:cool:

Good luck

just do it

To my mind some UFH and night rate heating of immersion. The amount required doesn't justify capital expenditure. But then Part L also comes into the equation.....

I'm looking at Nilan Compact P accompanied by PV.