Storage Heaters

[AGT]

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...)

For many decades the much-quoted downside of SHs has been the fact you need to anticipate the weather. Otherwise you face an unexpectedly cold day with no heat, or have excess heat on days when it is milder than you expected. SHs with decent insulation can hold their heat for several days and use thermostatically-controlled fans (or flaps) to manage the rate that heat is allowed to escape. Some have timer and temperature settings just as sophisticated as the central-heating controls you reference. So this "downside" isn't as dramatic as you might think.

A SH is of no use to someone without a ToU tariff. Until recently these offered exceptionally poor value. However along came Octopus and overnight electric is 7p/kWh compared with 5p/kWh for gas. Given the inherent real-world inefficiency of a gas boiler SHs are now cheaper than gas!

Couldn’t agree more

[Richard77]

How do they retain heat for days?

So you turn them on and they don't output heat?



Edit.... Bricks?

[Stinsy]

How do they retain heat for days?

So you turn them on and they don't output heat?



Edit.... Bricks?

Insulation

[Joeboy]

How do they retain heat for days?

So you turn them on and they don't output heat?



Edit.... Bricks?

Some heaters have a bimetal strip which auto opens and closes the top vent to allow heat to flow out through convection rather than conduction from the storage bricks to the metall carcass. Others have a manual control which opens and closes the flap. A SH with manual control will with the flap fully closed continue to radiate heat through the carcass to effectively heat a room (if sized right). On a 6 hr tou tarrif the SH will not emit all it's heat and will store more heat in each 24hr cycle than it releases. When fully charged they will hold and release heat for a couple of days.

Or they will switch off from grid earlier if you just run them as described. There are differing models, insulation levels, retro insulation etc. I found them to be an astonishingly simple way to extend the benefits of tou and Spring solar charging.

The 800W single bank units are a good way start. Once I remove them from our home I'll install a 800W unit in our son's house as he is going onto IO soon. I might also fit one in the cabin. Hard to simply give up such excellence

[AGT]

Joe, happy to take a couple of the small heaters off you, either come to you , or meet in Dundee when your heading to Edinburgh, don’t need the bricks either so easier to transport or catch up anywhere that suits
Let me know
Just picked one up last night in Strachan that’s some drive, didn’t like that road!

[Richard77]

How do they retain heat for days?

So you turn them on and they don't output heat?



Edit.... Bricks?

Some heaters have a bimetal strip which auto opens and closes the top vent to allow heat to flow out through convection rather than conduction from the storage bricks to the metall carcass. Others have a manual control which opens and closes the flap. A SH with manual control will with the flap fully closed continue to radiate heat through the carcass to effectively heat a room (if sized right). On a 6 hr tou tarrif the SH will not emit all it's heat and will store more heat in each 24hr cycle than it releases. When fully charged they will hold and release heat for a couple of days.

Or they will switch off from grid earlier if you just run them as described. There are differing models, insulation levels, retro insulation etc. I found them to be an astonishingly simple way to extend the benefits of tou and Spring solar charging.

The 800W single bank units are a good way start. Once I remove them from our home I'll install a 800W unit in our son's house as he is going onto IO soon. I might also fit one in the cabin. Hard to simply give up such excellence

Cheers for the info Joeboy....

You have 95kWh worth of them?
I can only see some 2/3kw max ones.

Is your 95kWh calculated by 7/8 hours worth of small units (~1kw)?

Sounds like magic!

*Searches gumtree/eBay/Facebook marketplace*

Are there any particularly good old models to look out for? Are the new models just as good? I seem to see most people on here getting old second hand ones.

[Stinsy]

SH capacity is usually calculated as the power of the element multiplied by 7hrs (based on ecconomy7).

If you're using them with vanilla Go you'll get 5hrs of capacity. Therefore 1500W * 5hrs = 7.5kWh. Look for "HHR" (High Heat Retention) models. These have better insulation so hold the heat for a few days. Some have electronic timers, which is useful if your house is unoccupied in the daytime. The older ones weren't particularly good at retaining heat, great if your house is occupied all day but you might need an alternative heat source in the evening...

[Richard77]

SH capacity is usually calculated as the power of the element multiplied by 7hrs (based on ecconomy7).

If you're using them with vanilla Go you'll get 5hrs of capacity. Therefore 1500W * 5hrs = 7.5kWh. Look for "HHR" (High Heat Retention) models. These have better insulation so hold the heat for a few days. Some have electronic timers, which is useful if your house is unoccupied in the daytime. The older ones weren't particularly good at retaining heat, great if your house is occupied all day but you might need an alternative heat source in the evening...

Thanks Stinsy....

I might try and pick a few up. The new ones looks quite expensive though, I gather that's why everyone scours the 2nd hand market!

I'll be honest I had never heard of them until this thread. What other wonders of the world am I missing out on living under this rock?!?

We haven't got flying cars and hover boards yet have we? Have we??

[AGT]

Watch out for the sizes as we control them via smart sockets so you can program schedules, I have the one and 2 element units only with each element around 850-900 watts so I’m happy switching 1800watts with them.

[Joeboy]

How do they retain heat for days?

So you turn them on and they don't output heat?



Edit.... Bricks?

Some heaters have a bimetal strip which auto opens and closes the top vent to allow heat to flow out through convection rather than conduction from the storage bricks to the metall carcass. Others have a manual control which opens and closes the flap. A SH with manual control will with the flap fully closed continue to radiate heat through the carcass to effectively heat a room (if sized right). On a 6 hr tou tarrif the SH will not emit all it's heat and will store more heat in each 24hr cycle than it releases. When fully charged they will hold and release heat for a couple of days.

Or they will switch off from grid earlier if you just run them as described. There are differing models, insulation levels, retro insulation etc. I found them to be an astonishingly simple way to extend the benefits of tou and Spring solar charging.

The 800W single bank units are a good way start. Once I remove them from our home I'll install a 800W unit in our son's house as he is going onto IO soon. I might also fit one in the cabin. Hard to simply give up such excellence

Cheers for the info Joeboy....

You have 95kWh worth of them?
I can only see some 2/3kw max ones.

Is your 95kWh calculated by 7/8 hours worth of small units (~1kw)?

Sounds like magic!

*Searches gumtree/eBay/Facebook marketplace*

Are there any particularly good old models to look out for? Are the new models just as good? I seem to see most people on here getting old second hand ones.

If I remember correctly it's based on 6hrs charging. Roughly 15.8kW potential charging but I never did charge them all fully at the same time. We had a few properties and anecdotal evidence fathered that shows the older 800W single standing units generally used in bathrooms took a better charge and outputting more heat than newer ones. No idea if it was a design change but we found that twice.