New storage heaters

[endecotp]

Isnt there an off-peak thing where its all the electricity at either night or day prices, not seperate wiring?

In an economy-7 installation, all the electricity used on the normal circuits during the off-peak period is charged at the off-peak price.

 

[Captain Nemesis]

Thats what I thought.

 

[SUNRAY]

I was just about to start a thread asking for advice as I've been getting conflicting advice. Hopefully this is not seen as unreasonable hijacking however I'll happily move it to a new thread.

As OP I have a rental flat with 3 1980's NSH's, 3.6KW and 2.4KW in lounge and 2.4KW in bedroom. A previous tenant used to hang wet washing over them to dry, all 3 had gone rusty and the internal overheat thermostat had tripped.

nov 2017 to april 2018 the property was empty for full refurb; kitchen, bathroom, total decoration, CU & accessories, carpets, the lot and my decorator took the NSH covers away to clean up and respray.

3 years on the tenant reported 2 of the NSH have failed and all 3 are rusty.

Agent sent in a local heating company to repair, they quoted £1200 to replace all 3 with Qrads and reconfigure CU to do away with E7. I haven't seen quote but agents says it includes an energy assessment, including immersion heater, showing no increase in running costs bearing in mind the inflated E7 day rate.

I've checked and find 3 failed elements and one internal overheat tripped, those 2 are working with one element each.

Contacting a refinisher he has come up with a figure of £200-£300 each to strip and refinish with a 2 part polymer heat resistant finish, another has quoted £800 to strip and powder coat, both seem very conversant with the product, knew exaclty which panels were being discussed etc. Working parts are available for these units but not external covers.

It doesn't make sense to me to spend £1K on 35 year old heaters.

I've checked with my EPC inspector, currently on 68D She indicates replacing with Qrads and removing E7 will place flat around 36F to 40E, instead suggests replacing lounge;
3.6KW dual feed with HHR NSH, one 2.4KW with Qrad will move it to 71C or
3.6KW dual feed with HHR NSH, both 2.4KW to HHR NSH will move it to at least 78C or possibly 81B depending on models used.

I've been sent a list of 'qualifying' HHR NSR's, am I right to think they only go up to 1.5KW?

I have no experience of running NSH's and I can't see how immersion heater can be cost effective unless very carefully manually controlled by tenant.

So my question is which of the 2 professionals is wrong?

 

[endecotp]

which of the 2 professionals is wrong?

This one, surely:

Agent sent in a local heating company to repair, they quoted £1200 to replace all 3 with Qrads and reconfigure CU to do away with E7. I haven't seen quote but agents says it includes an energy assessment, including immersion heater, showing no increase in running costs bearing in mind the inflated E7 day rate.

 

[SUNRAY]

This one, surely:

I'm sure you're correct but I'll happily say I'm out of touch with modern heating systems.

 

[flameport]

Whether 'modern' heating systems are the same price, cheaper or more expensive to run compared to 'old' storage heaters depends entirely on the usage of the building.

For those which will be heated for all or most of the day, old style storage heaters will be far cheaper as the electricity used is all on night rate.
Changing a situation like that to partly or wholly day rate will increase costs dramatically, 3x more would not be unusual.

If the place is only heated for some of the day, the total cost may be similar as although the electricity costs more, the amount used is less.

For the rare places where heating is only on for a couple of hours in the morning / evening and it's empty most of the time, day rate will be cheaper overall, but that's only due to the very short time that heating is used.

It's very easy for companies to quote the latter, however in reality it's rarely the case, as people are at home for substantial periods of time, and particularly with a rental, the use of the property will change over time so an installation that's cheap to run for a particular person can be outrageously expensive for someone else.

Modern storage heaters are none of the above, as they are a combination of a smaller amount of night storage at cheaper rate, plus additional day rate when extra heat is required. They are suitable for places that are empty for some of the day as they have better control over the heat output compared to old style storage heaters.

 

[SUNRAY]

Whether 'modern' heating systems are the same price, cheaper or more expensive to run compared to 'old' storage heaters depends entirely on the usage of the building.

For those which will be heated for all or most of the day, old style storage heaters will be far cheaper as the electricity used is all on night rate.
Changing a situation like that to partly or wholly day rate will increase costs dramatically, 3x more would not be unusual.

If the place is only heated for some of the day, the total cost may be similar as although the electricity costs more, the amount used is less.

For the rare places where heating is only on for a couple of hours in the morning / evening and it's empty most of the time, day rate will be cheaper overall, but that's only due to the very short time that heating is used.

It's very easy for companies to quote the latter, however in reality it's rarely the case, as people are at home for substantial periods of time, and particularly with a rental, the use of the property will change over time so an installation that's cheap to run for a particular person can be outrageously expensive for someone else.

Modern storage heaters are none of the above, as they are a combination of a smaller amount of night storage at cheaper rate, plus additional day rate when extra heat is required. They are suitable for places that are empty for some of the day as they have better control over the heat output compared to old style storage heaters.

Thank you.
So does the 1.5KW limit I believe I see make sense?

 

[flameport]

Old storage heaters were rated on the input, new ones are rated on the output, so new appear a lower rating, as the power output is spread over a longer period than the more traditional 7 hours of input overnight.

A new 1.5kW storage heater is typically 3.3kW input, which over 7 hours is 23.1kWh stored, or about 15 hours of output at the rated 1.5kW, and as they have electronic controls / timers / thermostats and in most cases a fan inside, it's assumed that the output won't be full all of the time. If it is particularly cold, the day rate 'boost' elements can be used to provide extra heat.

 

[SUNRAY]

Old storage heaters were rated on the input, new ones are rated on the output, so new appear a lower rating, as the power output is spread over a longer period than the more traditional 7 hours of input overnight.

A new 1.5kW storage heater is typically 3.3kW input, which over 7 hours is 23.1kWh stored, or about 15 hours of output at the rated 1.5kW, and as they have electronic controls / timers / thermostats and in most cases a fan inside, it's assumed that the output won't be full all of the time. If it is particularly cold, the day rate 'boost' elements can be used to provide extra heat.

Thanks Flame, I've been on an online calculator which shows 4.3KW of NSH or 1.9KW of Quantum, that makes a lot more sense now.

 

[Diver Fred]

I've checked with my EPC inspector, currently on 68D She indicates replacing with Qrads and removing E7 will place flat around 36F to 40E, instead suggests replacing lounge;

Do not remove E7 - in my book that is incredibly stupid. Maybe your assessor has misunderstood the electrical connection requirements.

EPC standards like Quantum rads - the rads are probably good for people out all day as they (should) retain heat all day and discharge it later in the day. You do need an E7 supply to charge the heater up and a 24 hour supply to control and power the fan assistance. There is NO manual control of energy input but is of energy (heat) output - thermostat and timer.

I have no experience of running NSH's and I can't see how immersion heater can be cost effective unless very carefully manually controlled by tenant.

Not sure how big the tank is. A small tank (20-25 Gals/100-125 lt) probably has one element - time switch will need to 2 power feeds; one E7 and one 24hour. Majority of tank heating on E7 with boost if needed on 24hour. Large tank (twice the size+ of above) will have two feeds and 2 elements; bottom element on E7, top element for manual boost.

Insulation is the important item to gain efficiency - I put 2 cylinder jackets on.

 

[SUNRAY]

Do not remove E7 - in my book that is incredibly stupid. Maybe your assessor has misunderstood the electrical connection requirements.

EPC standards like Quantum rads - the rads are probably good for people out all day as they (should) retain heat all day and discharge it later in the day. You do need an E7 supply to charge the heater up and a 24 hour supply to control and power the fan assistance. There is NO manual control of energy input but is of energy (heat) output - thermostat and timer.


Not sure how big the tank is. A small tank (20-25 Gals/100-125 lt) probably has one element - time switch will need to 2 power feeds; one E7 and one 24hour. Majority of tank heating on E7 with boost if needed on 24hour. Large tank (twice the size+ of above) will have two feeds and 2 elements; bottom element on E7, top element for manual boost.

Insulation is the important item to gain efficiency - I put 2 cylinder jackets on.

The heating contractors quoted to do away with E7, certainly not my choice [but nice on my pocket]. EPC assessor is saying keep E7 and at least one HHR NSH for which dual supply is fitted but the other 2 only have a single feed with can very easily be E7 or 24h, getting another feed to them will not be easy without surface mounting which I really don't want to do, even the ring circuit doesn't go near them. I think my easiest option is to fit time clocks at the NSH's if I need them.

The cylinder is a primatic with built in cistern and foam coated, I did fit a jacket too [twice] but it seems to disappear to make more storage space in th ecupboard. 2 heaters on a Horsmann E7Q timeswitch. On first cylinder there was just the one heater on E7 only.

 

[Diver Fred]

Don't see why E7 is dearer than single rate electricity - AFAIK the standing charge has been the same since the days of dual rate meters. Also AFAIK the day rate is the same price or at worse about a penny dearer; maybe checking on a comparison site will help.

What are 'HHR' Night Storage Heaters? A term I'm not familier with.

As for the cylinder - you probably have as efficient as possible hot water tank. With cylinder jackets disappearing the residents are using the cupboard as an airing cupboard. If they are like my wife taking that away is a great loss to their lifestyle - it means the residents will be using the NSH's to air or dry their clothes on. Best suggestion is to take the tank out, line with 25mm PIR and then plywood based Shower panel and put the tank and plumbing back. Add shelves to make an air cupboard.

 

[SUNRAY]

Don't see why E7 is dearer than single rate electricity - AFAIK the standing charge has been the same since the days of dual rate meters. Also AFAIK the day rate is the same price or at worse about a penny dearer; maybe checking on a comparison site will help.

What are 'HHR' Night Storage Heaters? A term I'm not familier with.

As for the cylinder - you probably have as efficient as possible hot water tank. With cylinder jackets disappearing the residents are using the cupboard as an airing cupboard. If they are like my wife taking that away is a great loss to their lifestyle - it means the residents will be using the NSH's to air or dry their clothes on. Best suggestion is to take the tank out, line with 25mm PIR and then plywood based Shower panel and put the tank and plumbing back. Add shelves to make an air cupboard.

Something like High Heat Retention, supposed to control the heat output more efficiently to make it last longer.

 

[SUNRAY]

OK job done.
We settled on Quantum 150RF to replace the old 3.6KW dual supply in the lounge
and a Newlec panel rad [went for 3KW as very little difference in price] to replace the 2.4KW E7 only in the bedroom.

For now we've [tenent and I] decided to not replace the E7 only second heater in lounge for now and to see how the HHR performs with a view to adding either anothe NSH or a panel later.


The quantums can be run on a single, permanent, supply using the inbuilt timer arrangements to energise the heat store at night, so as long as the E7 radial can be moved over to 24hr there's no problem fitting them.

 

[JohnW2]

For those which will be heated for all or most of the day, old style storage heaters will be far cheaper as the electricity used is all on night rate. Changing a situation like that to partly or wholly day rate will increase costs dramatically, 3x more would not be unusual.

I've just noticed this one.

I think you may be rather out-of-date. Until around 3 years ago, tariffs with day/night ratios of around 3:1 were not unusual. However, today on has to look quite hard to find even 1.5:1.

As nocturnal EV charging (hence nocturnal demand) increases, one imagines that the ratio will eventually 'flip' to the situation in which daytime electricity becomes cheaper - which has the potential to throw a spanner into the works of the storage heater market!

Kind Regards, John