New Heating System

[imdad]

Hi all,

In a nutshell, we have just moved into a 4-bed detached house built in the late 80s.

Currently it has a very small hot water cylinder with a traditional system in place

• loft water tanks etc.

The radiators are all shot and the shower water pressure is terrible. Ironically, the mains water pressure is really good as are the rest of the hot water outlets.

The house is not insulated well so we’re getting that sorted now too.

We’re in the process of getting quotes for new central heating with larger combi boiler but one chap has asked have I thought about going all electric?

I hadn’t but he outlined the benefits:

• more attractive than pipes
• silent operation (no gurgling water)
• powerful pressures hot water tank
• control each room temp

The only downside I can see is running costs but he has mentioned it won’t be long and solar panels will be affordable and account for most of the running costs?

As you can tell, I have no idea? I thought I’d ask if anyone is all electric, what type of running costs per month do you pay, if you
Don’t mind sharing.

Thanks

I wouldn't go old fashioned electric, no. Solar panels with an air source heat pump, however, could be s comprehensive renewable system, and has all the advantages you mention. And you would get the Renewable Heat Incentive.

I have this, 2 bed mid terrace, costs me 50 quid a month all in. Cost £10k to install, and I get £700 a year back from RHI.

Energy from electricity costs four times as much as energy from gas.

You have met a salesman who sells electric heating.

Dump him.

I thought it prudent to investigate a little further but this was my suspicion.

I have looked at a website with predicted costs but they are all based on ‘efficient running’ and actually mention ‘each radiator will probably only run for a 1/3 of the time’ due to how efficient they are.

Thanks

I have been through the costings for this and Electric is eye wateringly expensive compared to the alternatives.

The (approx) current price per KW/H for the different fuels is as follows:

Mains Gas : 3.2p
Oil: 4.7
Electric: 14p

My 4 bed detached is on oil and I calculate I use approx. 21,000 KWh of heating per year which is about £1000 - If I used electric it would be £3,000

This does not take into account any grants etc you may get for electric.

If you have tanks in the loft then you likely have a gravity fed system. Without a pump a shower is never going to be very powerful.

Be careful with a Combi boiler. It does work for some people, not others. It's only really suitable for a house with one bathroom.

And be careful when talking about water pressure. You need the pressure AND the flow. You can measure this yourself by filling a bucket from your mains kitchen tap and timing how long it takes to fill. From that, you can work out how many litres per minute you can get. Anything less than about 12 and you're in the danger zone. To fix this would require you running a new pipe from the street into the house. Whatever system you install you'll need to check this unless its another gravity fed system. This has a good explanation:- victoriaplum.com/blog/posts/understanding-water-pressure

For my install I had the pressure and flow (25 L/M). I put in a system boiler with a 250l pressurised hot water tank. I can run 2 showers at the same time easily and not lose pressure if someone flushes too.

It's amazing how much you love a well plumbed house.

Just had our system changed to a pressurised cylinder and new boiler, replacing a 24 year old one! The improvement in hot water pressure is amazing, showers are so much better. Never thought I’d get so excited about such a boring renovation, but it’s been brilliant!

If your on mains gas , I’d stay with on that, electricity is far more expensive for heating,

I looked into this but unless you already have solar panels the numbers just don't work. We've just replaced an old gravity fed system with a system boiler and it is excellent. I would highly recommend it over a combi for a 4 bed house. We've had both.

Thanks for this response, much appreciated. I have tested the kitchen tab. I can fill 12 l in about 30 seconds. I’m hoping this is good enough!

Would so be able to convert my central heating system to a pressurised one then?

Also, is 250l enough for a family of four. It won’t be long and we will be using two
Showers in the morning. We often run out of hot water at the moment but we have a small tank.

@imdad

Thanks for this response, much appreciated. I have tested the kitchen tab. I can fill 12 l in about 30 seconds. I’m hoping this is good enough!

Would so be able to convert my central heating system to a pressurised one then?

Also, is 250l enough for a family of four. It won’t be long and we will be using two
Showers in the morning. We often run out of hot water at the moment but we have a small tank.

24L / minute is plenty - a normal shower uses about 9 so you should be able to run two showers.

250L is actually more than you probably need. You could go lower. Remember the re-charge time comes into play here. If you have a decent boiler you should be able to heat a tank from cold in about 30 minutes or so.

We are a family of four, three bathrooms and we never run out of hot water.

Have a look at this:-

www.mrcentralheating.co.uk/water-storage/unvented-cylinders/indirect-cylinders/250l-system-fit-everflo-unvented-storage-cylinder

We fitted one of these. It is very well insulated and contains all the necessary plumbing for a system install. Just connect the boiler and pipes. And it's cheap! We placed our tank in the loft to save space.

We are very happy with our system now and especially the showers. Going from an electric shower to a mains pressure shower is a revelation!

We did actually think about installing one electric shower in case the boiler went wrong, but this proved unnecessary as the tank came with a built in emersion heater which would heat the tank if we lost the boiler.

I’m the opposite, I prefer our electric shower over the thermostatic one , the thermostatic one is too powerful and I have to turn the flow down as it’s like being jet washed 😮. And that’s on a combi. I like hot shower but not too powerful .

Remember a shower is only a few minutes. Power showers zip through the water, spend too long and a bath is cheaper.

Yes, your chap is after commission. Electric heating is eye wateringly pricey and unit prices are only going one way.

What type of boiler do you have? One plumber said ours might be ok. The other said it won’t work. It’s a Glow Worm system boiler - 18. It’s about 6 years old but seems to work fine. I might just see if I can add the water cylinder and change the radiators. They are all quite old, can’t be bled and the valves do no work.

I'm not boiler expert but an 18Kw boiler which is 6 years old should not need changing. I'd be surprised if it couldn't be used in an unvented install. Recharge time for a 250l at 18KW will be about 40 mins or so - not bad.

It's likely there will be new pipework required including a drain (overflow) from the tank. You may find that some of your taps need changing as they will be operating at a higher pressure as well as your toilet valves. Also a very small chance of leaks from existing pipes as they are all under more pressure but this is not common.

You've reached the limit of my knowledge now! I would advise you get a plumber who you trust, tell him you want to retain the boiler if poss and then go with his advice. Point him at the tank I linked to to see if it would work for you.

Thanks, a great help.

I can't advise on going electric, but I'd say it's certainly worth getting a few quotes. If you've moved to a different area, speak to neighbours, ask who their plumber/heating engineer is.

250litres is fairly common these days for an unvented cylinder, if you have room for it. It will run two or three baths, or several showers, and is big enough that you will probably only need to run the boiler morning and evening (which is a bit more economical on gas than running it every time you run a sink, like a combi). It weighs about as much as three portly people hugging, so may be better on the ground floor.

Running a new water supply pipe is easier than you think, and will improve flow dramatically. From your internal stopcock, I recommend you run a new 22mm pipe to the cylinder and bath, and another 22mm for your cold water supplies (especially the bath), with 15mm branches to everything else. Use full-bore service valves.

If you have tanks in the loft then you likely have a gravity fed system. Without a pump a shower is never going to be very powerful.

It would be if you have a shower coil in the hot water cylinder. That way you get mains pressure hot water for showers. That is what we are fitting.

I have all electric and my bill is approx £400 a month. Nightmare.

As for solar panels, bear in mind that they deliver most power between 10am and 4pm on sunny summer days

Just the time when you have the least need for electricity for heating, lighting and cooking.

Presumably, you offset the winter cost by feeding excess power back in to the grid in the summer.

It's not a paying proposition.

Electricity is such an expensive form of energy that you only use it for heating and HW if you have no alternative.

The feed in tariff for solar ended in 2019 to new installations.

Thank you for your detailed reply. This set up is what I am leaning towards.

Although, I had a chat with a plumber (who will confirm what he thinks when he visits the house next week) but he has suggested I don’t rush off and pay for a new boiler whilst mine is working. We have a Glow Worm Flexicom 18hx which apparently can’t be used with a vented system anyway so I would need to change that too!

He thinks that a good balance would be to increase the cylinder size to cure the hot water running out problem and install a shower pump to increase the shower flow! My only worry is we will be adding a 2nd bathroom soon with another shower?

I have read online though that with increased water pressure on shower thanks to pump, the loft tanks may not cope. Oddly, we have one water tank in the upstairs loft and then another in the extension loft which sits above the main bathroom downstairs.

The feed in tariff for solar ended in 2019 to new installations.

The government feed in tariff for solar ended in 2019 to new installations.

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