15 hours ago, CalvinHobbes said:

she just likes it about 23 degrees

Perfect temperature. It's what we keep our house at.

  

1 hour ago, Thorfun said:

“instant heat”

Not sure old people need instant.

 

33 minutes ago, Gone West said:

15 hours ago, CalvinHobbes said:

she just likes it about 23 degrees

Perfect temperature. It's what we keep our house at.

About my favourite temperature as well.

 

There is a bit to much hair shirtery when 20°C is quoted, even though that is about my mean temperature.

3 minutes ago, SteamyTea said:

Not sure old people need instant.

it's what the OP wanted! 🤷‍♂️shrug

1 minute ago, Thorfun said:

it's what the OP wanted! 🤷‍♂️shrug

  

22 hours ago, CalvinHobbes said:

bluntly mum requires intense heat

 

Surely the worst case scenario is that you use a fan heater to heat up the room quickly whilst the heat pump is providing background heating?  But then why is the room colder in the first place if you have asked the heating to maintain a constant temperature?

 

To me the central issue is whether the heating for the rooms housing the older person is compatible with the heating you want for the rest of the house.  I like it cooler at night so I set back my heating.  If I wanted part of the house at a constant temperature 24/7 then I would have to make that a separate zone.  Hard core ASHP enthusiasts abhor zones because they tend to make running the ASHP a bit more expensive.  So you pay a bit more to keep an old person comfortable; is that so terrible?      

method of heat source is irrelevant. 

 

What is the heat loss calcs for your desired internal temperature.

 

Size a unit accordingly.

2 hours ago, ReedRichards said:

worst case scenario is that you use a fan heater 

Sometimes the simple solution is best. You want one discrete space warmer, so boost it with an electric heater on a thermostat or timer. Or a radiating panel beside the comfy chair.

59 minutes ago, SteamyTea said:

  

   23 hours ago,  CalvinHobbessaid: 

bluntly mum requires intense heat

 

🤦‍♂️

 

need to learn to read. 

Edited April 1, 20242 yr by Thorfun

6 minutes ago, Thorfun said:

🤦‍♂️

 

need to learn to read. 

Well it could be an autocorrect typo.

 

Facts. Red and Orange lines electric costs heating crappy static caravan and a couple.of cabins through the summer. 

Blue line, electric cost to heat ,DHW and run a 90 sqm well insulated airtight house, and a few days of cabin usage. The drop off is the house drying out and soaking up the heat.

Yesterday we had some solar gain, and the ASHP never came on overnight as the house temp was stable.   

23deg might be needed in a drafty house, a well insulated, no draft house is a delight and like comparing apples and oranges. Keep the faith, insulate, make it tight as a drum and worry about something else.

 

6 minutes ago, Jenki said:

The drop off is the house drying out

Really quite a marked difference isn't it.

 

Makes me wonder why people want to add 'thermal mass' when it takes so much energy to heat up.

16 minutes ago, SteamyTea said:

Really quite a marked difference isn't it.

 

Makes me wonder why people want to add 'thermal mass' when it takes so much energy to heat up.

It's my assumption. Nothing has changed we set the heat pump up set the thermostat and off it goes, it was cold and windy in January so it wasn't a change in outside temps, so my assumption was it must be the concrete core(ICF BUILD), and the drying out of skim plaster etc using more heat. Once it was stable then the heat demands dropped. I've changed to Octopus energy now so can't use the same chart for February and March. But the electric figures are holding now at around £70/m - £90/m depending on cabin usage and  PV utilisation, which I'm delighted with. Makes battery storage a harder justification now.

 

25 minutes ago, SteamyTea said:

 

Makes me wonder why people want to add 'thermal mass' when it takes so much energy to heat up.

My house and many others have proved you don't need "thermal mass" to keep a house a constant temperature.  It's insulation and air tightness that does that.

44 minutes ago, SteamyTea said:

Really quite a marked difference isn't it.

 

Makes me wonder why people want to add 'thermal mass' when it takes so much energy to heat up.

 

free heating can be leveraged.

18 minutes ago, Jenki said:

my assumption was it must be the concrete core(ICF BUILD), and the drying out of skim plaster etc using more heat

Almost certainly is the reason.

Not only does water take around 5 times as much energy as concrete to heat up, once it start to evaporated, it takes silly amounts. Over 500 times the energy.

 

20 minutes ago, ProDave said:

My house and many others have proved you don't need "thermal mass" to keep a house a constant temperature

Been saying it for nearly 2 decades now, but not many people want to believe me.

3 minutes ago, Dave Jones said:

 

free heating can be leveraged.

What the (expletive deleted) does that mean.

excess solar  through heat pump into slab. the eddi has a feature where it can decide if its more cost effective to drive the heat pump over an immersion for example.

43 minutes ago, ProDave said:

My house and many others have proved you don't need "thermal mass" to keep a house a constant temperature.  It's insulation and air tightness that does that.

Plus MVHR?

16 minutes ago, Dave Jones said:

excess solar  through heat pump into slab. the eddi has a feature where it can decide if its more cost effective to drive the heat pump over an immersion for example.

You won’t have excess solar when it’s wintertime though. Plus, trying to operate a heat pump on sporadic pockets of sunshine is just barking mad. 

Don’t cry. There are people you can talk to   

23 hours ago, Nickfromwales said:

You won’t have excess solar when it’s wintertime though. Plus, trying to operate a heat pump on sporadic pockets of sunshine is just barking mad. 

Solar is only really crap from about the middle of December through to about the middle of January. Peak heating demand in most of the UK is in January but in the west country is February. Using a small battery to iron out the sporadic pockets of sunshine is a must it seems or the heat pump won't have time to warm up.

I'm not sure why many are against oversizing solar arrays so they work better in winter and clip in the summer. Panels are incredibly cheap if you buy them by the pallet. Inverters are hardly expensive and can be DC oversized if you need to. There are also techniques for spreading out the power band (e.g. east-west arrays).

Fitting them yourself is incredibly low effort if you have a good electrician that will sign off the inverter to grid bit (or some prefer to run the cabling themselves once the array is up). Anyone that has ever lifted a tile on a roof is capable of fitting them on a pitched roof and on a flat roof it can be as simple as a ballasted system. 

 

On 01/04/2024 at 10:59, SteamyTea said:

Makes me wonder why people want to add 'thermal mass' when it takes so much energy to heat up.

Is that not precisely the point? If it took that much energy to heat up it now has a store of energy which is released back to the house (presuming the thermal mass is on the inside of the thermal envelope).

 

23 hours ago, SteamyTea said:

What the (expletive deleted) does that mean.

 

Running heating systems on renewables. It gives you greener, more reliable power. We have had at least 20 power cuts in the last 8 years here it has been ridiculous but our solar and solar battery have run perfectly since they were installed 5 years back (we don't notice power cuts until the neighbours come round for tea).

 

Edited April 2, 20242 yr by NailBiter

1 hour ago, NailBiter said:

Solar is only really crap from about the middle of December through to about the middle of January

But you can get some good days, although quite short. This year we did Christmas day on boxing day and our lunch was all cooked via solar. The yellow is solar generation, green consumption, and blue below the zero line is battery being charged. The red is import electricity.

 

1 hour ago, NailBiter said:

(we don't notice power cuts until the neighbours come round for tea)

We get a texts - do you power? we answer yes, but the mains is down, similar the other days mains water was off, but we use a borehole.

1 hour ago, NailBiter said:

Solar is only really crap from about the middle of December through to about the middle of January. Peak heating demand in most of the UK is in January but in the west country is February. Using a small battery to iron out the sporadic pockets of sunshine is a must it seems or the heat pump won't have time to warm up.

I'm not sure why many are against oversizing solar arrays so they work better in winter and clip in the summer. Panels are incredibly cheap if you buy them by the pallet. Inverters are hardly expensive and can be DC oversized if you need to.

 

 

That rather depends on particular circumstances. Here solar is crap from the beginning of November to the middle of March. Dorset is pretty far south so will have better insolation than most of the country and individual location has a significant effect on energy availability.

 

 

Over sizing is not really a solution; if there's low insolation levels you won't harvest much energy however large the array. Ours is over 14kW peak and still produces next to nothing in the winter. Yes, panels are cheap but most people have limited space to put them. We've used all the available roofs, and I'm going to ground mount an extra 3+kW, just because I can; it won't make a meaningful addition to the energy produced in winter.

5 minutes ago, billt said:

and I'm going to ground mount an extra 3+kW, just because I can; it won't make a meaningful addition to the energy produced in winter.

My first array is at 45 degs and roof mounted - dreadful output in winter, not helped by trees and low sun. Our second array is ground mounted, but vertical, provides 200% the output of the first array in winter.

We have 6.9 kW on a due south facing roof in Devon, could hardly be better for insolation. But the generation in winter is only 1/10th of the summer peak, this is how it looked last year for the original 3.68 kW array. (The newer 3.24kW looks virtually identical, so the year's total was 7144 kWh which is 1032kWh per installed kW):