All Electric heating?

mike_2009

Hi,
Is it possible to build a house that has all electric space and hot water heating these days that meets Part L and DEAP? I'm building to passive standard but due to high build costs want to opt out of an ASHP initially to ensure I can get out of the ground! So I've 1.1Kw space heating requirement and it's a 3 bed house for hot water if that helps. I'll have Solar PV (8 panels). I'd be using a central electric water heater and electric space heating.
Thanks

Dardania

I don't know the answer, but am following with interest.
I wondered in the past if it was possible to put in sufficient insulation, and good enough controls, and then just use resistive heating - would be very elegant solution if possible.

sydthebeat

mike_2009 wrote: »

Hi,
Is it possible to build a house that has all electric space and hot water heating these days that meets Part L and DEAP? I'm building to passive standard but due to high build costs want to opt out of an ASHP initially to ensure I can get out of the ground! So I've 1.1Kw space heating requirement and it's a 3 bed house for hot water if that helps. I'll have Solar PV (8 panels). I'd be using a central electric water heater and electric space heating.
Thanks

if you are building to passive standard, then get passive certification as proof of energy efficiency.

You can argue compliance with the spirit of the building regulations with this certification of proof.

no certification = no proof = no argument

and to answer your initial question, yes, its possible to have all electric space and water heating and comply with Part L.... thats essentially what Heat Pumps do.

other methods would need to be assessed in full

looksee

Those of us who were around in the '70s however remember when the power would go off for hours and sometimes days at a time on a regular basis. If you did not have a gas cooker, some sort of oil or gas lamp and alternative heating you were cold and hungry! Those days could easily return - I am having air to water heating in a (non-passive) new house but there will be a stove - entirely redundant according to my architect - but I am not chancing it.

mike_2009

So there's nothing anyone can think of in Part L per se that precludes using purely resistive heating? It's DEAP where I think I'll need to focus and ensure it passes there. Is it possible that if it passes today, future DEAP changes could cause the same setup to fail at the end of building next year?

sydthebeat

mike_2009 wrote: »

So there's nothing anyone can think of in Part L per se that precludes using purely resistive heating? It's DEAP where I think I'll need to focus and ensure it passes there. Is it possible that if it passes today, future DEAP changes could cause the same setup to fail at the end of building next year?

Yes I can think of loads.

The primary energy factor is the main one.

The grid works at about 50% efficiency currently, so your 100% efficient electric heater is only working at 50% efficiency in real terms.

That's worse than a sold fuel stove.

Dardania

sydthebeat wrote: »

mike_2009 wrote: »

So there's nothing anyone can think of in Part L per se that precludes using purely resistive heating? It's DEAP where I think I'll need to focus and ensure it passes there. Is it possible that if it passes today, future DEAP changes could cause the same setup to fail at the end of building next year?

Yes I can think of loads.

The primary energy factor is the main one.

The grid works at about 50% efficiency currently, so your 100% efficient electric heater is only working at 50% efficiency in real terms.

That's worse than a sold fuel stove.

i must download a copy of DEAP and play with some numbers - really curious about this.

mike_2009

But with a Passive house and 1kW space heating load and 2.4kW Solar PV, surely that would offset the consumption figures? I took the preliminary DEAP XML and swapped out the ASHP with pure resistive but may have missed some critical figures. It appeared to satisfy DEAP but I'm not the right authority to call it....

sydthebeat

mike_2009 wrote: »

But with a Passive house and 1kW space heating load and 2.4kW Solar PV, surely that would offset the consumption figures? I took the preliminary DEAP XML and swapped out the ASHP with pure resistive but may have missed some critical figures. It appeared to satisfy DEAP but I'm not the right authority to call it....

if youre going passive, then forget about DEAP and concentrate solely on PHPP and get certification.

however if youre not getting certification then you need to comply fully with DEAP and that wont be easy.

DEAP and PHPP are very, very different analysis tools.... the former being very a very general comparison tool, whereas the other is a very details and specific to the individual property tool. So what one say is the energy demand may be complete at odds with the other.

for example im familar with two dwellings built in carlow about 10 years ago which were passive certified, but only reached a BER rating of B2 because their main space heating source was an electric element in the MHRV.

if you want to download DEAP and play with it fine, but as someone who has been trained in DEAP and working with it full time for the last 11 years, i can say im still learning aspects of it.... so i wont expect your calcuations to be all correct and in accordance with the methodology on your first few attempts.

so again, i have to stress with you... if going passive then get certified !!
if you go passive but dont get certed, you might find youve to add unnecessary bolt-on technologies in order to comply with DEAP

mike_2009

The Architect is saying I'll fail the Primary Energy Demand in PHPP so that route may also be an issue.
Their advice is to go to tender with a small ASHP and at build time make a decision regarding options and budget. Kicks the same can down the road but if the tender responses are unaffordable, which is quite possible, this issue may be moot anyway.
I'll return to this post at a later stage if not!
Thanks all.

0lddog

The low projected heat requirement suggests to me that what is needed is a fig leaf to satisfy compliance.
Would compliance issues be satisfied if OP were to install a small air - air heat pump ?

e.g. https://www.orionairsales.co.uk/samsung-maldives-cac-ac026fbrdeheu--wall-mounted-air-conditioning-25-kw--9000-btu-inverter-heat-pump-1956-p.asp

Would that sort of cost be bearable to OP ? ( obviously there would be installation & commisioning costs in addition to the equipment cost )
( OP, similar units also made by Toshiba, Daikin, Mitubishi Electric, Mitubishi Heavy, Panasonic etc. etc )

One of the criticisms of air - air heat pumps is their poor low temperature performance.
If this is a concern & OP is prepared to spend a little more then look at units such as

http://www.mitsubishi-electric.co.nz/heatpump/c/8221/hypercore-fh-high-wall-heat-pumps

In Europe, Mitsi sometimes market these under the name 'Zubadan' rather than 'Hypercore'.

Disclaimer : I know nothing about DEAP or about PHPP

mike_2009

I can get a willis heater for €150 and a central water heater for €500-600 compared with an ASHP and stainless steel cylinder. There's a significant difference in cost. The main difference is how DEAP would view this as it lacks the COP of an ASHP but I hope to have 2.4Kw of Solar PV. I really need someone to do the numbers in DEAP and determine if this is a runner, I have Nilan P and Ecodan QUHZ CO2 and other options all priced up which are the alternatives and suited to my house size / needs. This is a regulatory rather than cost issue for me currently.

caesarthechimp

How are you proposing to distribute the heat; hot water to rads from a central buffer tank, or storage heaters, or just simple wall mounted panel heaters?
A combination of solar PV and night tariff electricity might not be be too bad in terms of running costs, if you could get over the compliance issues.
Will there be any stove in the house?

mike_2009

I'll have underfloor heating / manifold all zoned for the ground floor, no loop upstairs, two electric towel rails in the bathrooms. No stove planned. It's DEAP that the issue with the Primary Energy Factor changing shortly.....

caesarthechimp

I was just thinking if you put in a wood pellet stove with external air supply, you could classify that as the main heating system in certain circumstances.

Deap Manual wrote:

A3.3 Highly insulated inadequately heated small dwellings.
In the case of highly insulated small dwellings, item (2) in A3.2 may not be realistic, for example a 3 kW gas fire could suffice to provide most of the heating needs. Accordingly, if the design heat loss (DHL) is less than 3 kW, the heating in the main room is the primary system in this case. Dwelling heat loss is defined in Section A3.5.

A stove with high efficiency and renewable pellet fuel might go some way towards solving your problem.
However this "accountancy method" is not going to work with electric underfloor heating, if it heats more rooms than the stove, then it would have to be considered the primary heater. Unless you had a back boiler to the stove, then it could work. You'd be claiming then that the electric was a secondary heater. But its would be entirely up to you whether you ever lit the stove in real life.
Of course, you're still left with the expense of installing a chimney or a double insulated flue. Still, it might be nice to have the stove there as an option for Christmas day and the like. You can buy the pellet fuel by the bag if you're not using much.