# Replacing central heating with electric rads



## goosebump (6 Aug 2016)

I recently got some advanced electric rads installed in a small extension we built. These guys:

http://www.haverland.co.uk/

They're pretty sophisticated re. programming, and can be centrally controlled with a WIFI unit, which you can control with your phone.

The rest of my house is heated with rads backed by a wood pellet burner. The system is about 10 years old, and will need replacing soon.

I live in an old cottage in a rural area. We have 3 bedrooms and a 3 other rooms, so we're not too big. Some parts of the house are damp, and could do with having a low level of heat year round, which isn't practical with a central system. Also, oil theft is a big issue around us. Lots of people have had thousands of euros drained from their tanks.

I was thinking of scrapping the central system and investing in the electric rads for every room. The practicality of the solution is really appealing to me. No more pellets, hoppers, oil tanks, servicing etc etc, and full control of the heating system year round.

Just wondering if I am missing anything.

I figure it could be more expensive in terms of heat generation, but that I will save by being able to programme different rads to be on at different times (and use thermostatic controls), rather than the current set up, where the heating in the entire house is just either on or off.

Would I need my power supply checked out? I guess I'd probably need to look at the fuse on the socket network? What about voltage into the house? Would 7 or 8 electric rads impact on the voltage available to other appliances?


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## Monbretia (6 Aug 2016)

Running costs I'd imagine would be the main disadvantage but if you can afford that then why not!  I put lovely fancy electric rads into a small extension where it wasn't practical to extend the central heating to, imported from UK with timers etc.  Cost a fortune to run, electricity bill went up dramatically, so basically have disconnected two of them in case anyone turns them on by mistake, left the bedroom working on a timer.


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## Leo (9 Aug 2016)

You're looking at adding 12+kW based on your assessment of 8 radiators. You'd need to calculate the real heating need to confirm that, there are online calculators that will help determine your needs based on parameters such as room size, aspect, insulation levels, etc.. 

Standard supply capacity in Ireland is generally 12kVA or 16kVA, so those radiators will consume much of that on their own. You'll certainly need to apply for an upgraded supply, there'll be a cost associated. You will also very likely need a new consumer unit, and will definitely need to run new cables to supply the rads. Just plugging these in to existing sockets will at best just trip the circuit or fry some cables.


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## goosebump (16 Sep 2016)

Leo said:


> You're looking at adding 12+kW based on your assessment of 8 radiators. You'd need to calculate the real heating need to confirm that, there are online calculators that will help determine your needs based on parameters such as room size, aspect, insulation levels, etc..
> 
> Standard supply capacity in Ireland is generally 12kVA or 16kVA, so those radiators will consume much of that on their own. You'll certainly need to apply for an upgraded supply, there'll be a cost associated. You will also very likely need a new consumer unit, and will definitely need to run new cables to supply the rads. Just plugging these in to existing sockets will at best just trip the circuit or fry some cables.



I've talked to my electrician and he has said none of this will be required. The suppliers (3 different ones) have said the same thing. Not sure what you're basing this on. The sockets are on different circuits. There would never be more than 3 rads on any circuit.


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## goosebump (16 Sep 2016)

Monbretia said:


> Running costs I'd imagine would be the main disadvantage but if you can afford that then why not!  I put lovely fancy electric rads into a small extension where it wasn't practical to extend the central heating to, imported from UK with timers etc.  Cost a fortune to run, electricity bill went up dramatically, so basically have disconnected two of them in case anyone turns them on by mistake, left the bedroom working on a timer.



I've done some testing with the existing rads.

Last year I spent €340 per month on pellets in Dec, Jan and Feb.

Based on my tests, the electric rads would cost:

€330 if drawing power 75% per hour
€220 if drawing power 50% per hour
€110 if drawing power 25% per hour

This is based on daily usage of approx. 11 hours per day in kitchen to 4 hours per day in bedrooms.


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## cremeegg (16 Sep 2016)

A house with 3 bedrooms and 3 other rooms and you are spending €330 per month on heating !!!

Just get a oil fired burner, even if you were robbed every year it would be cheaper.


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## goosebump (17 Sep 2016)

cremeegg said:


> A house with 3 bedrooms and 3 other rooms and you are spending €330 per month on heating !!!
> 
> Just get a oil fired burner, even if you were robbed every year it would be cheaper.



That's only in the 3 coldest months of the year, and that includes water heating. Its also an old stone cottage, so doesn't retain heat as well as a modern house. And the house doesn't have any zonal control, so the fuel source is less of an issue than the house.

I don't spend anything on solid fuel, either.

Annually, I spend about €1,500 on wood pellets, which wouldn't be dis-similar to what a lot of people in older houses are spending on oil + solid fuel.


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## shweeney (18 Sep 2016)

Heat pump?


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## goosebump (19 Sep 2016)

shweeney said:


> Heat pump?


After 10 years with pellets I'm looking for something low maintenance. I don't mind spending a bit more for that. I am away from home 2-3 days per week, and I need something that my wife can manage without having to have a degree in engineering.


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## shweeney (19 Sep 2016)

goosebump said:


> After 10 years with pellets I'm looking for something low maintenance. I don't mind spending a bit more for that. I am away from home 2-3 days per week, and I need something that my wife can manage without having to have a degree in engineering.



I don't see why she would need a degree - most new builds are using them now, they can't be that complex.  I can't see that electric will be anything but more expensive than oil or gas if you're using it to heat rads directly, using a heat exchanger can multiply the efficiency. There was an article in the IT about them last week:
http://www.irishtimes.com/life-and-...y-theme-but-will-save-you-thousands-1.2789810

Or look at converting to a gas tank - gas is harder to steal 
Calor have some sort of "free boiler" offer if you switch to them.


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## cremeegg (19 Sep 2016)

goosebump said:


> After 10 years with pellets I'm looking for something low maintenance. I don't mind spending a bit more for that. I am away from home 2-3 days per week, and I need something that my wife can manage without having to have a degree in engineering.



This quotation should be emblazoned on every wood pellet boiler.


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## goosebump (20 Sep 2016)

shweeney said:


> I don't see why she would need a degree - most new builds are using them now, they can't be that complex.  I can't see that electric will be anything but more expensive than oil or gas if you're using it to heat rads directly, using a heat exchanger can multiply the efficiency. There was an article in the IT about them last week:
> http://www.irishtimes.com/life-and-...y-theme-but-will-save-you-thousands-1.2789810
> 
> Or look at converting to a gas tank - gas is harder to steal
> Calor have some sort of "free boiler" offer if you switch to them.



Anything that is based on moving parts, heating elements, fans, cables, sensors, water and pipes is going to be complex. I've spend time in my boiler house more than once on Xmas Day.

See my post from 8 years ago:

http://www.askaboutmoney.com/threads/gerkros-woodpecker-pellet-boiler-explained.99360/

The key to the electric rads is the control (and to a lesser extent the efficiency), in they they cut in and out as required, and retain heat after they cut out.

I tested yesterday with 4 rads, running for 4 hours (=3.5KW when all were heating). I set a target temperature in the 4 rooms of 22'C (much warmer than I'd want, but I set it to simulate colder weather).

The cost for that 4 hours was about €1.60, based on a price KW/H of €0.19.

My full installation would be 10KW, so extrapolating out, that's somewhere in the region of €200-€300 per month depending on the weather and usage.

Cost of 8 rads = €3,200.

One other consideration is that I can locate the rads anywhere in the room I want, rather than having to put them where the existing pipework is. This is a plus for me, as I can locate them nearer the damper corners of the house.

*Thanks for link about free boiler. Going to follow that up.


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## goosebump (20 Sep 2016)

Leo said:


> You're looking at adding 12+kW based on your assessment of 8 radiators. You'd need to calculate the real heating need to confirm that, there are online calculators that will help determine your needs based on parameters such as room size, aspect, insulation levels, etc..
> 
> Standard supply capacity in Ireland is generally 12kVA or 16kVA, so those radiators will consume much of that on their own. You'll certainly need to apply for an upgraded supply, there'll be a cost associated. You will also very likely need a new consumer unit, and will definitely need to run new cables to supply the rads. Just plugging these in to existing sockets will at best just trip the circuit or fry some cables.



I some more checking on this too.

I have 4 socket circuits, 2 up, 2 down. Each is 20A rated, which apparently can tolerate 4KW current. That's 16KW total, whereas I hope to install 10KW of space heating. You obviously need to check that your sockets are evenly distributed around your circuits, particularly in rooms that would generate more current than others (eg Kitchen). You should get an electrician to confirm this, particularly in older builds, but in general, provided your wiring was done professionally to being with, you should be able to use 8-10 of these rads in a standard 3-4 bed house.

That said, I am not an electrician. I plan to get an electrician to confirm that I will be able to use these rads.


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## Leo (20 Sep 2016)

goosebump said:


> I some more checking on this too.
> 
> I have 4 socket circuits, 2 up, 2 down. Each is 20A rated, which apparently can tolerate 4KW current. That's 16KW total, whereas I hope to install 10KW of space heating. You obviously need to check that your sockets are evenly distributed around your circuits, particularly in rooms that would generate more current than others (eg Kitchen). You should get an electrician to confirm this, particularly in older builds, but in general, provided your wiring was done professionally to being with, you should be able to use 8-10 of these rads in a standard 3-4 bed house.
> 
> That said, I am not an electrician. I plan to get an electrician to confirm that I will be able to use these rads.



That's what I was getting at. Radial socket circuits are designed to have the capacity to handle your regular appliances. Everyone's use will be different,   Given your current spending on fuel, I fear you may need to go for the largest electrical rads available to match your current heat output. What's the kWh output rating of the pellet boiler?

3 of the 1500W rads will exceed the total capacity of a single radial circuit, drawing 20.45A assuming a fully resistive load. 3 of the 1000W ones will draw 13.64A, so with those you'd need to be careful there are no other heavy load items on the circuit. Even using a vacuum cleaner at the same time the heating is on would likely trip the circuit. For the kitchen circuit, using the kettle alone might be enough to trip the circuit with a single radiator on. It's for this reason storage heaters are wired into dedicated circuits, and not simple plugged into sockets.

10 of the bigger rads on at the same time would consume almost the entire capacity of a typical domestic 16kVA supply, and trip a 60A main breaker, that's before you switch on a single light.


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## goosebump (20 Sep 2016)

Leo said:


> That's what I was getting at. Radial socket circuits are designed to have the capacity to handle your regular appliances. Everyone's use will be different,   Given your current spending on fuel, I fear you may need to go for the largest electrical rads available to match your current heat output. What's the kWh output rating of the pellet boiler?



Boiler is rated 20KW, but I doubt if transfers anywhere near that into the rooms. Its 12 years old, and is in a Barna shed at the gable wall. Lots of pipework too. 



Leo said:


> 3 of the 1500W rads will exceed the total capacity of a single radial circuit, drawing 20.45A assuming a fully resistive load. 3 of the 1000W ones will draw 13.64A, so with those you'd need to be careful there are no other heavy load items on the circuit. Even using a vacuum cleaner at the same time the heating is on would likely trip the circuit. For the kitchen circuit, using the kettle alone might be enough to trip the circuit with a single radiator on. It's for this reason storage heaters are wired into dedicated circuits, and not simple plugged into sockets.



I'm actually only installing 8.5KW. The other 1.5KW is already there, in the extension, on its own circuit. This will include only 1 x 1500W rad, which will be the only rad on the circuit. Beyond that, the most that will go on a circuit is 2KW. 

I suspect I may be underspec'ing slightly, but based on tests so far I really don't think I need anywhere near 20KW. I am to install them piecemeal, leaving the larger, more frequently used rooms until December, so I can make a more informed decision about capacity. We're not one of those families with ice-water running through our veins. 17'C is ambient for me. I hate it when the house is too warm.



Leo said:


> 10 of the bigger rads on at the same time would consume almost the entire capacity of a typical domestic 16kVA supply, and trip a 60A main breaker, that's before you switch on a single light.



I'd melt if I had that much heat in the house.


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## Leo (20 Sep 2016)

Good stuff, just wanted you to be aware of the potential downsides. Best of luck with it, I'd be interested to hear how you get on once the system is in and you have the controls/timing tweaked to use just what you need where and when you need it.


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## noproblem (20 Sep 2016)

I have an oil central heating system with 3 heating zones, nothing special or anything.
 Zone 1 heats downstairs.
 Zone 2 heats upstairs.
 Zone 3 heats the hot water.
I use "Solo" radiators (which have a fan that throws out the heat) in all the rooms, except the bathrooms. I find the rads fantastic, extremely economical and use just a little more that 1 fill of oil per year to heat a 2,500 sq ft 2 storey house, average insulation and 16 years old. (TOTAL 1,200 LITRES) Check out the rads on the internet, you'll never look back, believe me.


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## SparkRite (20 Sep 2016)

Leo said:


> 3 of the 1500W rads will exceed the total capacity of a single radial circuit, drawing 20.45A assuming a fully resistive load. 3 of the 1000W ones will draw 13.64A, so with those you'd need to be careful there are no other heavy load items on the circuit.
> 
> 10 of the bigger rads on at the same time would consume almost the entire capacity of a typical domestic 16kVA supply, and trip a 60A main breaker, that's before you switch on a single light.



Just to be pedantic Leo, it appears you have based your calculations on the old 220VAC domestic supply which is now 230VAC, has been for some time. This puts the load(s) at approx. 19.5A and 13A respectively. However the point you make is still most valid.


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## goosebump (21 Sep 2016)

noproblem said:


> I have an oil central heating system with 3 heating zones, nothing special or anything.
> Zone 1 heats downstairs.
> Zone 2 heats upstairs.
> Zone 3 heats the hot water.
> I use "Solo" radiators (which have a fan that throws out the heat) in all the rooms, except the bathrooms. I find the rads fantastic, extremely economical and use just a little more that 1 fill of oil per year to heat a 2,500 sq ft 2 storey house, average insulation and 16 years old. (TOTAL 1,200 LITRES) Check out the rads on the internet, you'll never look back, believe me.



That's pretty good, but you have zones, and I don't.


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## noproblem (21 Sep 2016)

That's not a problem goosebump, you could still use the radiators as they're the item that saves on oil usage. Consider the amount of water in the average radiator and then get your head around the fact these rads only use aprox 1/4 litre, doesn't take one long to gauge the amount that does not need to be heated to get a room warm/hot or whatever, plus the safety factor for children as the rads don't get hot, just blow out the hot air. Like I said, look them up as they would be ideal for your situation. By the way, I have no connection whatsoever to the company or product, apart from having them installed to heat my home.
*WELCOME TO AUBREN LTD :: SOLO RADIATORS*
*You have just accessed the latest in Water Based Heating and Air Quality Management.*
Hydronic Heating is water based like conventional systems, but unlike convention, is based on patented Solo hydronic heating units which reduce running cost dramatically, are extremely small, and allow endless control of area by area temperature. No other system offers the precise control and economy, resulting in a significant reduction in fuel bills. In our climate, we can get the four seasons during a typical day. Solo Hydronic software instantly adjusts heating levels to maintain comfort in step with fluctuating weather conditions.No other system can react this quickly. Solo was styled to enhance the decor in all locations, and is available in different finishes.


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## Leo (21 Sep 2016)

SparkRite said:


> Just to be pedantic Leo, it appears you have based your calculations on the old 220VAC domestic supply which is now 230VAC, has been for some time. This puts the load(s) at approx. 19.5A and 13A respectively. However the point you make is still most valid.



D'oh!! You're right as ever.


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