Help - new house has a system boiler!

[mareep]

In our old house we had a combi boiler which worked great for us. The new one has a system boiler with a massive tank (it heats more water than we used at the old house in a day.

Is there anything we can do except 1) rip out a fairly new boiler 2) heat lots more water than we need or 3) only heat water every other day?

None of these seem like great solutions to us.

Set your hot water timer for an hour or 2 each day. Doesnt need to be on all day.

@dementedpixie yes, but that's still heating much more water than we will consume, thus expensive to run.

Its not expensive to heat hot water for an hour or so a day and then you have hot water ready to use when you need it. (I assume its a gas boiler)

I have a gas boiler and hot water cylinder and find it works well and isn't expensive to run if you use timers and a thermostat

We have one, it's well insulated and costs very little to run, we pay next to nothing for gas in the summer when we don't have the heating on (we cook with electricity).

I hate boilers with tanks. Ime you never have the hot water when you need it, and often have the issue of running a bath and the hot water runs out half way through. You then have to wait hours for it to heat up to do anything requiring hot water. Really annoying. We ripped ours out and fitted a combi.

[quote mareep]@dementedpixie yes, but that's still heating much more water than we will consume, thus expensive to run.[/quote]
no it isn't

the cylinder will stop demanding heat from the boiler as soon as it reaches target temperature. This might take around half an hour. You can set the HW timer to run for half an hour or so before and during your morning and evening shower sessions. If you are very profligate in hot water usage you can increase these times a little.

I expect your new cylinder is silver or white. It is very well insulated and very little heat escapes. If it is in an airing cupboard, you will find it loses hardly enough to warm the clothes, except for the heat escaping from the hote pipe while running (you can lag these if you like).

Interestingly, you will very likely find it uses less gas in summer months than your previous combi does.

this is because with a combi, every time you turn a hot tap on, the boiler fires up, heats itself, its heat exchanger, and some litres of water inside, in addition to whever water runs down the pipes and out of the tap. When you turn the tap off, the boiler, its water and pipes lose this heat to the air, until next time you turn on a tap, when it all happens again.

System boilers are fine. If you have a big house, you're almost certainly better off with one anyway. Much better water pressure, Just have it on for an hour or something a day. It costs buttons to heat.

Yep, we've just had one fitted. It's great in that you can have someone filling the kettle, someone else in a shower and someone flushing the loo and it just copes with all of that.

It fills a bath if you want it to. But we just have it on for an hour a day and it does 6 showers. Any more than that and we have to put it on again for half an hour or so. Over the summer we used bugger all oil but had lots of showers.

@RavingAnnie

I hate boilers with tanks. Ime you never have the hot water when you need it, and often have the issue of running a bath and the hot water runs out half way through. You then have to wait hours for it to heat up to do anything requiring hot water. Really annoying. We ripped ours out and fitted a combi.

We don't have any of those problems. We keep it switched on for a couple of hours in the morning and all evening, but it's never on for long at a time, it only takes 20 mins to heat another tank up if you do use it all up having a bath.

When the central heating is on, that helps heat the water whenever you’ve set it. The tank is insulated and lagged and designed to keep heat in so you’re not heating the whole tank from cold every time it clicks on.

For the amount it will cost to change, it’s unlikely to be more cost effective than leaving the system as it is until you need to change it.

Plus too the government may be offering help to change to heat source in future

"You then have to wait hours for it to heat up to do anything requiring hot water. "

I think this must have been quite an old system. A 3kW electric immersion heater warms water at the rate of about 1 litre per minute, and a bath holds about 100 litres, so should be ready in 100 minutes. A modern gas boiler has anything from five to ten times as much power, and a modern cylinder with a modern gas boiler will heat much faster. Also, it is modern practice to have larger cylinders, often around 250 litres, which would run two baths without running cold.

modern cylinders are also very well insulated, and will stay hot for days. I don't know how many, but I particularly remember having a very welcome hot bath on a Sunday night after working all weekend with the power turned off.

We have a pressured tank and the water stays on all the time, with the heating on a timer. Because the megaflo tank is so well insulated it costs very little to have hot water available all the time.
I'd run the system for a quarter before I was too worried OP. My neighbour has a combi and pays lots more than us.

I was told combi boilers are really only suitable for smaller houses, I have 3 bed/2 bath. I do know someone with a bigger house that fitted 2 one runs upstairs heating and hot water and the other downstairs.

@PigletJohn we have a tank system with a white covered main tank and a red and white cylinder above.

A plumber recently told us that these need specialist plumbers to service the boiler etc, but I can't remember the name.

"G3 qualification" (ticket) to install or work on unvented cylinders. Many boiler service people will have one now, it isw getting more common, so you can have them both safety-checked and serviced in the same call.

The white thing is a pressure vessel for the hot tap water. it contains a rubber ballopn of air to absorb the expansion as the water heats up. It is made of stainless steel as you might drink tap water.

The red thing is much the same but for radiator water. Not stainless as you would not drink it.

Thanks @PigletJohn. Much appreciated.

In the last few months I've used £20-£30 per month of gas (actual readings) and that's with gas central heating, hot water and a gas hob with a conventional boiler. When we got a new boiler we got a similar boiler and kept the feeder tanks and hot water cylinder as it suits our house better than a combi would.

Ok, expensive is relative (although our new energy provider thought we'd use £200 a month!), I'm more about being as energy efficient as possible.

Our water meter shows we use on average 160 litres a day (both hot and cold). @PigletJohn will the cylinder stay warm for a couple of days? it's a white one

@mareep

Ok, expensive is relative (although our new energy provider thought we'd use £200 a month!), I'm more about being as energy efficient as possible.

Our water meter shows we use on average 160 litres a day (both hot and cold). @PigletJohn will the cylinder stay warm for a couple of days? it's a white one

We use a lot more electricity than gas tbh even though we have gas central heating

Our gas bill is tiny during the summer months.

If the tank is correctly insulated and lagged then it should be quite efficient. If you also lag the hot pipe work it will also help.
You have a reasonable system you just need to work out when your water demand is and control the heating accordingly.
Most systems have 2 control points, one for the Central heating and radiators and one for the Hot water tank, this will also have a thermosat to shut off the boiler once the set temp is reached.
You can improve efficiency but reducing the water max temp to below 65'C.
If your thermostatic control is old these can simply be updated, see Screwfix or Toolstation.

@mareep

Ok, expensive is relative (although our new energy provider thought we'd use £200 a month!), I'm more about being as energy efficient as possible.

Our water meter shows we use on average 160 litres a day (both hot and cold). @PigletJohn will the cylinder stay warm for a couple of days? it's a white one

If you don't use it...

I expect it will.

give it a try.

If not, lag the pipes around it, especially the ones coming out near the top, and any that are hot tp the touch.

Also, take photos, including the pipes and any pump you can see (especially if yellow) because there is a method used to keep pipes to distant taps constantly warm, which is wasteful of heat.

BTW energy from electricity costs around five times as much as energy from gas, so use gas, if you can, for all heating and hot water.

Cost of lighting is insignificant, as long as you have energy-saving or LED bulbs. Halogen downlighters and spots are much more expensive to run.

phone chargers are so small you can hardly measure them.

the most expensive appliance in our house is the tumble drier, because it is a heavy load that runs for hours in a week.

Washing machines and dishwashers only run the heater for ten minutes or so to heat each hot cycle so cost little. The motor and pump are trivial.

Electric heaters are expensive, but if you have a baby or frail person in the house, an oil-filled electric radiator at a low setting during the night probably costs less than running the whole house CH. Turn it off when the CH is on.

BTW I just checked our gas meter readings. In summer it is between half a cubic metre and 1 cu.m per day (mostly for hot water via cylinder)

A cubic metre is about 11.2 kWh
we pay 3.06p per kwh for gas
So gas usage costs us around 70p a day (plus standing charge) for hot water

obv winter costs more as the heating is on.

Yours may be different.