ICF Build - right heating system

AdamAntsy

Ok I've been yo-yo'ing around this for quite some time and perhaps another opinion may sway it

I'm leaning heavily to an ICF construction, good double glazed windows, heavy insulation on floors & roof area. Also adding MHRV is on my list.

Given all that, I had originally thought of a geo-pump and UFH... however I'm wondering if the capital outlay (principally the geo-pump) is worth it if my build will be as efficient as I hope... it may take a long time to recoup. Habitable area is not far under 5000sq ft so the pump size may also require an expensive 3-phase installation.

Finally, I'm worried on UFH that if the house overheats, it might take a long time to dump the stored heat.. would Rad's be better? (Converse is true and its too cold..)

So - given other choices such as Oil, and Air-Water, does anyone have an opinion on what might suit or is it more a question of taste.. love to hear from anyone with an ICF build and how their system has performed for them.

sydthebeat

AdamAntsy wrote: »

Ok I've been yo-yo'ing around this for quite some time and perhaps another opinion may sway it

I'm leaning heavily to an ICF construction, good double glazed windows, heavy insulation on floors & roof area. Also adding MHRV is on my list.

Given all that, I had originally thought of a geo-pump and UFH... however I'm wondering if the capital outlay (principally the geo-pump) is worth it if my build will be as efficient as I hope... it may take a long time to recoup. Habitable area is not far under 5000sq ft so the pump size may also require an expensive 3-phase installation.

Finally, I'm worried on UFH that if the house overheats, it might take a long time to dump the stored heat.. would Rad's be better? (Converse is true and its too cold..)

So - given other choices such as Oil, and Air-Water, does anyone have an opinion on what might suit or is it more a question of taste.. love to hear from anyone with an ICF build and how their system has performed for them.

your heat source should be directly related to your energy demand... it doesnt really matter what construction system you have once its built correctly.

with ICF you should be assuming a decent air tightness result once you include for adequate tightness provisions on the timber roof structure, and around your openings.

what u values are you looking to achieve in the floor, walls and roof?
how are you complying with Part L 2008?

i am personally of the view that geothermal heat pump systems with UFH are still too expensive to make them viable in this country... add to that the lack of knowledge of this technology in the trades, and the ability / inability to get the system serviced (companies going under every day!)

reduce your heat demand as much as possible... then determine your heating system.....

eg should you get your energy demand low enough, you can heat your house by meansof a small electrical element in your HRV system..... ie air to air with no plumbing required for space heating!! you are very close to passive standard with this though....

AdamAntsy

An Air->Water pump would, I presume meet the renewable component for part L, at less cost than a geo install and give a better response to demand than a full cycle on the geo pump, which may make it preferable despite a reduced COP.

If it's an oil boiler, than I think a solar DHW system might be required, and reduce oil consumption to about 5 months of the year..

Thats the thoughts the reality is often different!

Of course - the combined cost of the oil boiler/tank installation and solar collector & assorted tanks might not be that far off the cost of a geo-pump. Hence the headache!

WRT U Values - I'm guessing here but approx .2 on the walls I have to be hitting low 1's and roof values I guess hitting the same as the walls.

(Still very early stage of speccing these out in terms of actual insulation to go into these, but this is the targets to hit I think).

Self-builds leave you with an awful lot to learn in an awfully small amount of time

sydthebeat

AdamAntsy wrote: »

An Air->Water pump would, I presume meet the renewable component for part L, at less cost than a geo install and give a better response to demand than a full cycle on the geo pump, which may make it preferable despite a reduced COP.

only heat pumps with a certified seasonal COP of greater than 3.0 can be considered as 'renewable'..... only a DEAP calculation will tell you if you are in compliance or not...very very risky to begin construction without this calculation..!!

AdamAntsy wrote: »

If it's an oil boiler, than I think a solar DHW system might be required, and reduce oil consumption to about 5 months of the year..

again, only a DEAP calculation will tell you for sure what you need...
in my experience solar panels + dedicated wood stove is required...

AdamAntsy wrote: »

Of course - the combined cost of the oil boiler/tank installation and solar collector & assorted tanks might not be that far off the cost of a geo-pump. Hence the headache!

the combined cost will of an oil boiler, rads, solar collectors.... will still be lower than a GSHP + UFH....

AdamAntsy wrote: »

Self-builds leave you with an awful lot to learn in an awfully small amount of time

.. thus the necessity to engage a professional....

AdamAntsy

Yes agreed - a lot of companies have some bias as they sell a range of the technology, so not always sure how much they have me as the central interest.

If anyone can PM me a recommended and independent energy consultant, I'd be interested.

Thanks for the advice.

sydthebeat

AdamAntsy wrote: »

Yes agreed - a lot of companies have some bias as they sell a range of the technology, so not always sure how much they have me as the central interest.

If anyone can PM me a recommended and independent energy consultant, I'd be interested.

Thanks for the advice.

who is supposed to be certifying your build??

can they not do this?? if not id be looking elsewhere for a certifier...

AdamAntsy

Still up for grabs - just acquired planning permission and will be sourcing an engineer for the structural certification. I'll admit I'm a bit lost in the forest of available professional services.