Replacing an old Economy 7 heater with a modern one, will I save much on electric bills?

Stubod

Hi all,

We have old, (single supply) economy 7 storage heaters that have been in the house since it was built 30+ years ago. Now we have a smart meter I have been doing some hour by hour analysis of our electric usage. As expected the most energy is used for the first three hours from mid night when  the heaters "boot up". ie, by the time the tariff goes back to daytime the heaters have been off for a while and are losing heat, and by the evening some are almost cold.

If I changed a heater for a more modern one with a 24hr supply, (to the timer unit), would it be better to set them to come on a little later, eg about 4:00AM? That way the heater would stay hotter until later in the day?

(Last Winter we found that we only needed to use 2 heaters with backup from a multi fuel burner and some occasional convector heating in rooms which were only used occasionaly).

Thanks for any replies...

mmmmikey

Hi - I did the same a couple of years back and it definitely made a worthwhile difference in the evening. Didn't save me any money but the house was warmer in the evening. But I've ditched the storage heaters now in favour of other heaters I had.

Another option you might like to consider is switching to a TOU tariff like Octopus Agile and switching the heaters on and off with smart switches whenever the Agile rate is cheap. At the moment, you'd save a fair bit of money doing that and you'd find your storage heaters get topped up in the afternoon as well as overnight. But Agile prices vary so there is some risk. There's also some configuration to do. It's fairly straightforward, you use IFTTT. Suggest you have a look at the IFTTT website and if it looks easy to you it's a viable option - but if you're thinking what on earth is that I'd give it a miss.

Also, it might be worth seeing if you can control all the storage heaters centrally using a contactor that switches all the circuits on and off together and is controlled by a single timeswitch / smart switch. This is definitely a job for an electrician though, but may not cost a lot compared with individual timeswitches / smart switches and has the advantage that you only need to configure and check one timeswitch / smart switch.

Hope this makes sense

Gerry1

Two things to do before you consider upgrading to HHR NSHs.

Firstly, are you using the existing NSHs optimally?

https://www.youtube.com/watch?v=UeB3Xf_qKvA

Secondly, a failed element can explain why a heater gets cold in the evening.  However, it's very easy to check and replacement elements are cheap.

When the cheap rate kicks in, turn absolutely everything off except one NSH and count the number of times per minute that the meter's red light flashes.  For example, if it's marked 1000imp/kWh (impulses) and it flashes 40 times per minute then the NSH is drawing 2.4kW.

Then check the input power rating of the NSH; it'll be on its metal plate or you can look it up online.  If the heater is rated at 3.6kW then it's likely to have three 1.2kW elements but one has failed.

matelodave

As he's got a smart meter, presumably with an IHD (thats how he knows what is going on) he probably doesn't need to count flashes.

A 3 kw heater will show 3kw being consumed on the IHD and a 3.6kw one will show 3.6kw.

Stubod

mmmmikey said:

Hi - I did the same a couple of years back and it definitely made a worthwhile difference in the evening. Didn't save me any money but the house was warmer in the evening. But I've ditched the storage heaters now in favour of other heaters I had.

Hi and ta for the reply...

..can I ask what heating system you changed to??

I would love to get away from NSH, but can't really find a cost effective alternative at the mo.

Did think abuot getting some solar panels and maybe topping up the heaters during the day from these, (if that is even an option??)

Gerry1

matelodave said:

As he's got a smart meter, presumably with an IHD (thats how he knows what is going on) he probably doesn't need to count flashes.

A 3 kw heater will show 3kw being consumed on the IHD and a 3.6kw one will show 3.6kw.

Written to be inclusive of other readers, not just for those who have smart meters.

A 3kW heater won't show 3kW being consumed if an element has failed after 30 years.

Alnat1

Stubod said:

Did think abuot getting some solar panels and maybe topping up the heaters during the day from these, (if that is even an option??)

Many winter days you won't even generate 1kWh, definitely not enough to power the heating.

markin

If you are boosting using daytime energy then yes you will save money.


Many are supplementing or completely replacing with air to air heat pumps, Also known as A/C mini split systems.

Combined with Solar they will run on solar at times in all but the dead of winter, and the summer export makes up for a lot of the winter use, But It's important you get the best export price with Octopus.

mmmmikey

Stubod said:

mmmmikey said:

Hi - I did the same a couple of years back and it definitely made a worthwhile difference in the evening. Didn't save me any money but the house was warmer in the evening. But I've ditched the storage heaters now in favour of other heaters I had.

Hi and ta for the reply...

..can I ask what heating system you changed to??

I would love to get away from NSH, but can't really find a cost effective alternative at the mo.

Did think abuot getting some solar panels and maybe topping up the heaters during the day from these, (if that is even an option??)

I think my heating system is best described as hybrid - meaning I've got one of everything that was ever made

My general strategy is to provide background heat with Fischer Future Heat clay-filled electric radiators - very expensive to buy but they were in the house when I bought them. Last winter I only used these overnight when E7 was cheap, but found that they kept the houe comfortably warm until about 11:00 as the clay cooled down. This winter, I'll top them up during the day using cheap rate electricty when it is available - I've just switched to Octopus Agile.

I use a log burner in the living room which keeps that room lovely and warm and also keeps the chill off the rest of the bungalow on all but the coldest days. The logs are free - I bought a few acres of woodland - but there's a lot of effort in collecting them. I love it but for others it might be a chore - each to their own.

I have bottled gas heaters in the kitchen/dining room and conservatory which I use as and when required. These are modern blue-flame units with on-off thermostatic controls and modern safety features that are great at pumping out large amounts of heat very quickly. Bottled gas was much cheaper than daytime electricity last winter but the economics have changed, so I'll probably increase the background temperature this winter and reduce the use of the bottled gas.

I have an ASHP in the master bedroom which was expensive to buy but has the advantage of providing aircon in the summer which was why I bought it. It doesn't work very well when it's below freezing outside (lots of noise and not much heat) so I have a fan heater to provide early morning heat when it's very cold outside. All operated automatically with smart controls which use an outdoor temperature sensor to decide which heater to run.

I rely on the electric radiators in the other bedrooms as and when needed, which is not very often so hardly worth spending on anything better.

The bathroom has a wall mounted IR heater to give a quick burst of heat if needed during the day, and a wall mounted fan heater to provide extra heat when showering and to dry out the room afterwards. I'm planning to fit an electric towel rail in there but that's part of a bigger project that involves moving a door so not sure if I'll get it done this year.

Finally, I have a garden room / workshop which I spend a lot of time in during the winter months. That's heated with a blown air diesel heater of the type used in long distance lorries when they're parked up for the night.

This might sound like a bit of a hotchpotch but it's evolved over a few years and (finally!) works very well for me. With electric heaters you always get 1kWh heat out for every 1kWh you put in, but there are lots of different types and considerable scope for reducing energy costs by making sure that you get just the amount of heat you need where and when you want it.

As far as solar panels are concerned (which I also have, they were on the bungalow when I bought it) as @Alnat1 points out they don't generate a useful amount of electricity for heating when you need it. But they can be a very good investment if you're on E7 as they reduce your day time usage which is when rates are expensive.

Hope this helps, or at least triggers some ideas, Mike

markin

Heat pumps have a cop of 3 to 5 that means 1kwh of energy in is 3 to 5kwh of heat out, An A/C unit chosen for heating rather than cooling a single room should have no problem heating a large room or most of a floor, They will often quote a floor area of up to 50sqm, or 120sqm.

Gerry1

markin said:

Heat pumps have a cop of 3 to 5 that means 1kwh of energy in is 3 to 5kwh of heat out

Those figures seem a bit optimistic, especially for an ASHP.  Even a GSHP might struggle to reach COP5 consistently.