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What electric heating and DHW for small new build flat?


Mr Punter

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36 minutes ago, joth said:

I'll say it once more: put any spare £ you want for hugs from planet earth into insulation.

That is quite an interesting idea.

Has anyone worked out the price difference between installing ordinary plasterboard and that aerogel backed plasterboard.  Then compared that to say fitting a heat pump over a storage heater.

I still think that one 10 kW inline water heater for all the hot taps and modern storage heaters is the cheapest option and the most environmentally benign.

Does anyone have the proposed CO2 figured for grid supplied electricity that SAP is changing to?

 

The 2018 SAP document Table 12 says 0.233 kg CO2/kWh with a primary energy factor correction of 1.738.

Gas is 0.210 kg CO2/kWh with a primary energy factor of 1.122.

So 0.405 and 0.236 respectively.

But I am not sure if they are the latest numbers.

Edited by SteamyTea
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Having insulated my house reasonably well with aerogel, I think that instantaneous space heat demand is no more than about 3kW under normal circs.  So I could replace the combi for the rad circuit with a Willis heater, thus the question in another thread.

 

By the time you look at the gas standing charge, capex for new emitters of any sort, grid declining intensity, etc, and the fact that this house will probably be pulled down in five years, 'instant' heating beats storage from a money ("total cost of ownership") and carbon pov, I suspect.

 

Rgds

 

Damon

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3 hours ago, joth said:

I'll say it once more: put any spare £ you want for hugs from planet earth into insulation. That stuff is hard to retrofit, especially underfloor. This will reduce heating (and cooling) requirements at zero incremental cost over time.

 

As it stands, with gas heating, the heating cost for the 1 bed flat will be about £100 per year.  Water heating is about £80.

 

There is a limit to what can be sensibly improved by adding insulation.  I could put some heat recovery ventilation but it would need to be small and idiot proof to run.

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3 minutes ago, DamonHD said:

Single-room MHRV such as I have in two rooms?

 

Rgds

 

Damon

 

Thanks Damon.  That may work well.  Do they count in SAP?  Do you have a suggested make?  What rooms do they go in?

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2 hours ago, Mr Punter said:

Do they count in SAP? 

I think they do.

Do a text search on that SAP document I linked to earlier.

 

With a small flat, I would have thought that ventilation was more important.

I have a small house (smaller than some of your flats), if I lived up country, I would have fitted MVHR by now, as it is, I can get away with open windows for the majority of the year, though this does chuck out the heat I put in during the previous night.

Worth remembering that when a storage heater is charging up, it shuts down most the the heating.  Why they can be good working with PV, even in winter as you may only need a kWh or two a day to keep the chill of a place.

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  • 4 months later...

My first flat was a new build one bedroom flat  all electric that was 25 years ago

storage in hall

storage in lounge with convector

panel heaters everywhere else

electric shower.

 

E7 supply no hassle.

 

now

insulate to the max.

storage in hall

storage in lounge with convector

panel heaters everywhere else

electric shower.

 

so the only change would be to insulate to a higher standard to reduce heat loss.

 

 

 

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8 hours ago, Mr Punter said:

 

Sadly it will be gas combi boilers x 3 I think.

Honestly don't be sad. Insulate well, control heat losses through ventilation. Reduce heat demand and it becomes much less critical what the source is. For a rental flat using something with minimum capital outlay and easy for any random tenant to understand and operate is of great value. Heating technology is always advancing and much easier to change a boiler at some point in future than improve critical errors in the design/build of the fabric

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