Storage Heaters

[Moxi]

I suppose to do that and meet the msc requirements for BUS you just need the surveyor to accept that your personal max temperature requirement is around the 18 degree mark?

Moxi

[Stinsy]

I'm surprised the official sizing calculation doesn't account for secondary heating...

[Moxi]

I'm surprised the official sizing calculation doesn't account for secondary heating...

Any secondary heating makes it hard for them to record the carbon savings I guess and it’s less neat for the national audit office to account for multiple heat sources probably?

Moxi

[Stinsy]

I'm surprised the official sizing calculation doesn't account for secondary heating...

Any secondary heating makes it hard for them to record the carbon savings I guess and it’s less neat for the national audit office to account for multiple heat sources I guess.

Moxi

None of those are good reasons to fit an inappropriate HP!

[Moxi]

No but since when has Whitehall worried about common sense and the practical?

Moxi

[Andy]

"
"It seems to me that it is best to fit an undersized HP and rely on secondary heating (log burner, resistive electric, etc.) on the very coldest days."

Thats my philosphy also but the MSE does not allow it so they put in big HPs that will not modulate down enough and change rads and pipes to achieve MSE objectives for a few days a yr.

I struggle to imagine that a small HP (3-5kw) running 24/7 is not enough. That is 72-120 kwh/day! How many people use more than that ?
Come on tell me if you need more than 5kw 24/7.

I _need_ a 12kw heat pump! At the coldest, it was maxed out at 3.68kW continuously. Not everyone lives in Southern England ;P. We had the 5kW stove on as well.

[Fintray]

"
"It seems to me that it is best to fit an undersized HP and rely on secondary heating (log burner, resistive electric, etc.) on the very coldest days."

Thats my philosphy also but the MSE does not allow it so they put in big HPs that will not modulate down enough and change rads and pipes to achieve MSE objectives for a few days a yr.

I struggle to imagine that a small HP (3-5kw) running 24/7 is not enough. That is 72-120 kwh/day! How many people use more than that ?
Come on tell me if you need more than 5kw 24/7.

I _need_ a 12kw heat pump! At the coldest, it was maxed out at 3.68kW continuously. Not everyone lives in Southern England ;P. We had the 5kW stove on as well.

You must live somewhere in the Artic Circle!
Yeah, between the 11th March and the 5th April I had 9 days where I used more than 120kWh/day.

[Stinsy]

I _need_ a 12kw heat pump! At the coldest, it was maxed out at 3.68kW continuously. Not everyone lives in Southern England ;P. We had the 5kW stove on as well.

Respectfully, no normal house “needs” a 12kW HP. If the heat loss calcs come back with that answer, upgrade the insulation and redo the calcs!

As above: there is a decades long tradition of oversizing heating systems ingrained in the trades. Even if they do the calcs accurately they fit the next size up or the one above that. Whereas sizing down is a better idea and augmenting with a secondary heat source in unusually cold conditions.

[Andy]

I _need_ a 12kw heat pump! At the coldest, it was maxed out at 3.68kW continuously. Not everyone lives in Southern England ;P. We had the 5kW stove on as well.

Respectfully, no normal house “needs” a 12kW HP. If the heat loss calcs come back with that answer, upgrade the insulation and redo the calcs!

As above: there is a decades long tradition of oversizing heating systems ingrained in the trades. Even if they do the calcs accurately they fit the next size up or the one above that. Whereas sizing down is a better idea and augmenting with a secondary heat source in unusually cold conditions.

It was -14ºC . We do have quite long periods at -6ºC, so the extra power gives us the flex to recover from the hot water tank heating cycles.

[AE-NMidlands]

It seems to me that it is best to fit an undersized HP and rely on secondary heating (log burner, resistive electric, etc.) on the very coldest days.

The one thing that leaps out at me is that to use cheap-rate power to charge up a SH you need to anticipate the need a day ahead...
Most people's central heating including mine uses a house thermostat to control the (on/off) output from the boiler, so it's just reactive. The programmable thermostat has significantly different settings for different times of day, but it is still reactive, like (I imagine) lighting a WBS.
And electricity for those of us without an EV is still twice the price of gas. So maybe worth having a HP but hanging onto a gas fire for localised heating in an occupied room at the coldest time of year? (Unless you are planning to remove the gas entirely to avoid the standing charge...)