Summer Water Heating, Elec Vs. Oil?

[Andy Spencer]

Hi all

Don't know whether there are any heating experts on the forum. We are in the sticks so are on oil central heating. Question: is it cheaper / better to heat hot water during summer (if it ever arrives!) from oil boiler or immersion heater when central heating not on?

Don't have economy 7 so pay 10.2pence per kwh electricity. Oil is now about 65p per litre. Just over 10kwh of energy in a litre of oil so say 6.5p per kwh. Boiler runs at 80% efficiency 'on paper' so just over 8 p per kwh so in theory still cheaper than immersion. However there must be big losses from the boiler system just heating hot water - the heat losses from pipework and the water jacket in the boiler once the system shuts down must affect this figure.

Any ideas? Coming to conclusion there's probably not a lot in it, but keeping boiler active on occasions is better than letting it sit for 6 months unused.

 

Cheers

[maca]

Sorry but lots of unknown factors,

 

First how much water do you need to heat each day?

 

How is the water used ie; washing up clothes washing baths or showers?

 

How many people in the house their ages and requiments?

 

Boys use less water than girls when washing, boys have the water hotter than girls do.

 

The list can go on so look at what you think the family usage is then double it and you should have a starting figure for your requirements.

 

Without knowing how good your system heats water compared to an immersion heater in the tank would not like to say which would be the best and cheapest.

[brumster]

I understand where you're coming from - we used to be on oil. I bet once you factor in the loss of the heat through the pipes/coil in the tank, heat soak out of the tank as you mention, it struck me there probably wasn't a fat lot of difference. I guess one question is whether you use a full tank of hot water in a day anyway?

 

We moved to gas over 12 months ago, and took the opportunity to move to a modern cylinder and unvented system. I tell you one thing - the new cylinder holds the water at temperature for so much longer than the old lagged copper effort. When the engineer installed it, before he got the boiler working, he rigged it up so that we could at least use the immersion for some hot water. We heated the tank and the water coming out of it was still hot 2 days later! I was amazed, the old cylinder would never have managed that, water was luke warm by 24 hours (airing cupboard was nice and cosy though). You can tell the difference because the airing cupboard doesn't get anywhere near as warm any more.

[fry61]

Only ever use electric immersion when our "summer" is hot enough to need the air con running;which generally is around 2/3 weeks a year. The rest of the time consider that the "losses" are warming the house & keeping the clothes nicely aired. Thoughts on the system standing idle are same as with an engine;best if it is run regularly.

[femster87]

Not based on the scaldings I get when I use the shower after Ballast......

 

I was going to say that Rob. Girls have the shower freaking hot. And then moan about being hot fews mins after shower.

[Guest marsbar]

Have you considered Solar heating?

Very efficient in summer months at no cost, just the capital outlay.

There is a good website www.navitron.org look for the glass tubed ones quite cheap.

Failing that friend has just put 4kw of solar panels on for £4500 inc a switch tge heats his hot water.

Getting 27kw per day last week.