Storage Heater Cost/Benefit Calculation Check

ch_152

Hello all.

Been in this flat for nearly 3 years now. It's a maisonette and the top floor bedrooms get very cold (poorly insulated roof)

The previous owner removed the two storage heaters from the upstairs bedrooms, replaced with simple plug-in heaters which I set timers to run using Tapo switches.

I was looking to possibly reinstate storage heaters in these rooms as the plug in heaters are costly to run (of course), but it seems it would not be that sensible a move, financially, but was hoping to get a sanity check on my calculations, and to make sure there's nothing else I'm missing...

Taking the main bedroom as an example:

• I've assumed that I run the plug in heater for 3 hours in the morning and 3 hours in the evening
• This has a rating of 2kW
• I'm on agile, and have averaged the unit cost for last winter (Nov-Apr inclusive) during the morning and evening periods at 22p and 19p, respectively.
• This results in a cost of ~£2.45 per day, or £445 per year (for the 6 months when it's below 10 degrees outside).
  

• I will control the Quantums so that they are supplied with electricity for around 6 hours per night (let's say 00:00 - 06:00)
• Looking at a 2.2kW rated unit in the bedroom (although should probably should go bigger)
• The average rate for agile between 00:00 and 06:00 last winter was ~16p/kWh
• This results in a cost of ~£2.13 per day, or £387 over the year.
  

So the saving by installing the storage heater in that room would only be ~£57. New, the Quantum QM100RF is over £800, and even second hand are upwards of £400. Plus electrician bills to wire up.

So it seems like it's definitely not worth the investment (while I do like this flat, I won't be living here forever)? Or have I missed something?



Worth noting that on a standard E7 day/night tariff of approx 30p daytime and 12p night-time the calculated saving comes out at over £350 - somewhat more appealing.

QrizB

If the bedrooms only require a few hours of heat each day, storage heaters are unlikely to make sense financially.

I'd also suggest that you're hugely overestimating the heat demand of your bedroom; 12kWh (2kw for six hours total) is roughly a quarter of the total daily heating demand of my 3-bed semi.

FrugaiMacDugal

ch_152 said:

Hello all.

• I will control the Quantums so that they are supplied with electricity for around 6 hours per night (let's say 00:00 - 06:00)

You should be sleeping then, a panel heater maybe an hour before bed and rising, just to take the chill off the room, all that's needed.

subjecttocontract

Have you run calculations on the cost of alternative heaters ? E.g portable Calor Gas heater.....heater cost say £100 + 15kg gas bottle @ £80. That gives approx 50 hours of heat and replacement bottles are approx £40. Would be a lot cheaper.

matelodave

DO NOT USE PORTABLE GAS HEATERS IN THE BEDROOM

As others have said, you probably don't need to heat the room for three hours in the mornings and another three in the evenings. Even if you do the thermostats should control the the temperature and reduce the overall power consumption so its unlikely to be a continuous 2kw for three hours. IMO storage heaters aren't ideal for bedrooms as they take in heat overnight and then deliver it during the day until they are lukewarm come the evening

Why do you need to heat the bedroom for three hours night and morning how much time do you actually spend getting dressed or undressed ?

I'd suggest an hour before you go to bed and an hour before you get up should be more than adequate to take the chill off. If its cold overnight then an electric blanket would be much cheaper to run and would heat you rather than the whole room.
TBH a quick blast with a fan heater would be more than sufficient for us whilst we got dressed or undressed and dived into bed.

lohr500

subjecttocontract said:

Have you run calculations on the cost of alternative heaters ? E.g portable Calor Gas heater.....heater cost say £100 + 15kg gas bottle @ £80. That gives approx 50 hours of heat and replacement bottles are approx £40. Would be a lot cheaper.

I'm not sure about that. A 15Kg Calor butane exchange bottle costs £50 in my area.

1Kg of butane gives +/- 13.5kWh. So 203kWh from a full cylinder.

£50/203 = £0.246 per kWh.  Isn't that about the same cost pr kWh as a standard variable electricity tariff?

Add to that the issue of the water vapour generated by a calor heater which may cause mould/damp in the room, the low risk of carbon monoxide poisoning if the ventilation is poor or the device goes faulty and the cost of buying the heater unit and the one off cost for bottle rental. 

Given the choice of a portable calor heater or a plug in electric heater, I'd use the plug in electric heater every time.

wrf12345

Electric blankets if rooms only used for sleeping? Sleeping in a cold bedroom is actually good for health, BTW.

subjecttocontract

* Oil filled radiator.
* Inverter air conditioner.
* Wall mounted fan heater.

Swipe

In a medium sized bedroom at say 10C, a 2 or 3KW fan heater on for 10-20 mins while I get ready for bed is more than enough to take the chill off for me.  As suggested, an electric blanket is a game changer, even if just to warm up the bed before you get in.

EssexHebridean

Although the Quantums are very good at retaining their heat, they do still let out some heat during the charging process, so if you like a room to be unheated while you are actually sleeping, they may well prove to be less than ideal for you. The other issue is largely as said - that they're not really a very efficient way of ensuring that a room is warm for you to get up in the morning (dependant on your rising time, it  may well be that you are trying to heat and charge simultaneously which isn't the most cost-effective way of using them) and there will also be some occasions where the unit's own intelligent charging just gets caught out for some reason and you end up needing to use the boost function in the evening too - and yes, if you would otherwise be using a panel heater, that's not going to beany more expensive in terms of a daily cost, BUT the heaters themselves are of course a lot more expensive in the first place! 

I'd agree with others saying to evaluate whether you actually need heating as long as you are currently using it for, and additionally look at options like electric blankets.

squirrelpie

Add some insulation, and maybe improve the airtightness?