Wood burner & electric heater help

coolasacucumber

I live in a small 1 bedroom terraced house. I have a great wood burner that heats the whole house when going. Downstairs is open plan, about 25m2. Currently I have a 1kw  wall mounted electric radiator to warm the mornings and times when the fire isn't on, but it really isn't doing very well. Some of the heating calculators tell me I need 2.5-3kw to heat the space. I have an electric heater in the bedroom & bathroom, and a water heater all linked to bluetooth plugs, so I have them all on timers etc.

What type of heater should I go for? I know with electric heaters 3kw is 3kw, whether a £50 Argos heater, or £500 fancy thing, but even so there is so much choice.

Basically I want it to heat up as quickly as possible. Does that lend itself more to a convection heater than say an oil filled radiator?

For example Argos have a £40 3kw convector heater that looks fine, but is there any merit in spending twice or 3 times that on an oil filled one?

Am I complicating an incredibly simple decision?

Thanks in advance!

Ectophile

An oil filled radiator is slower to warm up when compared to most other heaters, and also slower to cool down when you turn it off again.  Nice for background warmth, but not if you're in a hurry.

A convector heater is little more than a box with slots at the top and bottom, and a heating element in the middle.  It heats up very quickly.  They heat the air in the room, rather than the things in the room.

Radiant heaters, such as the quartz or halogen ones, tend to heat the things they are pointed at, while doing little to heat the rest of the room.

Fan heaters are effectively a convector heater, but with a fan to spread the hot air around better,  Of course, they are noisier than other heaters.

danrv

I’ve just bought five of these.
https://www.toolstation.com/2kw-convector-heater/p98046
Instant heat, 3 power settings, thermostat and timer all for under £20.
I use them on the 750w setting as the rooms are small to medium size.
An oil filled radiator would take a while to heat an open plan area. 

matelodave

A reasonable rule of thumb is about 100w/sq.m. You can do more complex heatloss sums but for your 25m2 then 2.5-3kw sounds about right, however just sticking one in the middle will still take a fair amount of time to heat the space, so you might be better having two, one at each end of the room.

If they are thermostatically controlled, they'll still only deliver as much heat as required so having two 2kwh heaters wont cost you any more in energy to heat the same space to the same temperature, but it will do it faster and more evenly

There really isn't any point in getting anything different to the Toolstation ones that danrv is suggesting unless you feel a need to spend extra money on something a bit posher - TBH for £20 I'd just go an get one and use it with your existing heater and see how you get on.

danrv

matelodave said:

A reasonable rule of thumb is about 100w/sq.m. 

Useful to know. Not sure how to calculate a hallway with stairwell and landing though. 

matelodave

danrv said:

matelodave said:

A reasonable rule of thumb is about 100w/sq.m. 

Useful to know. Not sure how to calculate a hallway with stairwell and landing though. 

It's not precise, I'm sure you could have a bit of a guess. As I said, you can go on line and use some of the heat loss calculators if you want to be more accurate.

We get away with about 50w/m2 but that's because it's underfloor heating so evenly warm all over and it's on all day and evening. and even overnight we only turn it down a couple of degrees, so it will run all night if it's everso cold.

However, if we do let the place cool down too much it can take a couple of days to get it back up to temperature again. We could increase the heating unit flow temperature to make it do it a bit faster but then it's efficiency suffers. As we are at home all day nearly every day, we like the place warm and comfy all of the time rather than needing to rapidly heat it for an hour or so in the mornings, letting the place get cold during the day and then reheating it for a few hours in the evening.

coffeehound

Best choice of heater type depends on the layout I suppose.  If the staircase is open, then a convector won't work so well as the heat will disappear upstairs and create a corresponding cold downdraught.  Another panel heater like a Dimplex OPX (secondhand from eBay) would be a good choice in that case -- either on feet or wall-mounted.

If the staircase is closed off then a cheap fan heater like a 2 kW one for £8.39 from Toolstation might be a good fast complement to the existing panel heater

danrv

matelodave said:

danrv said:

matelodave said:

A reasonable rule of thumb is about 100w/sq.m. 

Useful to know. Not sure how to calculate a hallway with stairwell and landing though. 

It's not precise, I'm sure you could have a bit of a guess. As I said, you can go on line and use some of the heat loss calculators if you want to be more accurate.

We get away with about 50w/m2 but that's because it's underfloor heating so evenly warm all over and it's on all day and evening. and even overnight we only turn it down a couple of degrees, so it will run all night if it's everso cold.

However, if we do let the place cool down too much it can take a couple of days to get it back up to temperature again. We could increase the heating unit flow temperature to make it do it a bit faster but then it's efficiency suffers. As we are at home all day nearly every day, we like the place warm and comfy all of the time rather than needing to rapidly heat it for an hour or so in the mornings, letting the place get cold during the day and then reheating it for a few hours in the evening.

Best way to run it, low and slow.
A similar system with radiators I guess would function the same.
The hallway with stairwell will need at least a 2kw radiator which will rack up the energy costs so leaving that area unheated for now. Maybe the largest Dimplex Quantum would be best there as it’s the largest area. 
All other rooms have 750w convectors on low. 

Petriix

If you're thinking longer term, an air-to-air source heat pump (basically air conditioning with reverse mode which heats rather than cools) would be more efficient. At certain temperatures they can output 4 to 5 times the heat of the electricity you put in. However there's obviously a large initial outlay which will take some considerable time to recoup in electricity savings. Definitely worth looking into though.

danrv

Petriix said:

If you're thinking longer term, an air-to-air source heat pump (basically air conditioning with reverse mode which heats rather than cools) would be more efficient. At certain temperatures they can output 4 to 5 times the heat of the electricity you put in. However there's obviously a large initial outlay which will take some considerable time to recoup in electricity savings. Definitely worth looking into though.

Thanks.
That”s probably the only heating system that’s going to work for me as a replacement for the warm air heater.
I read that with a multi split air to air, it’s approx. £1000 installation cost for each indoor unit. Six needed plus the outdoor one.
I seemed to have dragged the thread over to my heating situation. Hope the info is helpful to the OP.