New boiler prob needed before winter. Midlife towers is a big old place, solid walls with no insulation on many rooms, but I’m gradually getting to some and adding insulation before replastering. Rooms in roof, again, I’ve insulated nearly half of it, and will eventually get the rest done. Currently there are 15 radiators and two bathrooms, we’d like to add another bathroom and prob another two/three radiators. Should I just whack a big combi in, or are there real paybacks now from solar or heatpumps?

Not sure of the costs and economics of different heat sources but don’t think the payback on ground source or solar heating will rival gas at the moment. Not to say it shouldn’t be done though especially if you’re interested in that type of thing. Very good real savings can be made by installing clever heating thermostat things. themostat valves on individual radiators means you can set the lesser used rooms to lower temperatures. Eliminate the possibilty of convective air movement through draft elimination, shutting doors etc. can all make huge differences. Obviously the insulation will help too.

My Grandfather installed solar water heating a few years ago knowing damn well he’d never get economic benefit in his lifetime. He’s an engineer and generally fascinated by that type of thing. If the weather’s good then they’re massively effective. Pricey to install full system though I think.

If you’re going for 2 extra bathrooms etc, then have a look a a sealed System boiler and an Unvented hot water cyclinder.

As for alternative sources of heat, I can’t really comment, there’s nothing that is common enough that I could say is worth having.

British gas are currently developing a gas boiler which will generate electricity, and sell it back to the supplier when you’re not using it all, I’m trying to get one on trial when the time comes, along with the smart meter that tells you what you’re using 🙂

If you have a modern condensing system boiler on ( as paul says ) an unvented hot water system you’ll do just fine. Put all of your extra money and effort into insulation and then some more insulation. you’d be amazed how many people just throw their heat away.
Edit. it may be worth fitting a dual coil hot water tank if you do go down the unvented route so that you can upgrade to solar at a later date should you wish.

Your system is definitely too big for efficient use of a combi. Go for a normal condensing boiler with an unvented pressurised tank for the water – something like a Megaflow. Ground source heat pumps are good but total installation cost about £18k including digging in all the piping, and they work best with underfloor heating.

Whatever you do, go for proper wall mounted thermostats in each room to control the heating temp and on/off times

A room stat in very room? MAdness 🙂

That means a zone valve under the floor for every room, extending the system would become a mare, never mind the amount of cable and the size of the junction box you’d need to run 15+ room stats

Don’t know why it would be madness. Kitchen/dining, hall/landing, lounge, plus 3 bedrooms. I agree its quite a lot of extra work, but not that bad and it would give very efficient control of temperatures and times which was the original point

Heat pumps tend to work with slightly lower water temp. so good for underfloor heating or suitably designed rads. May not be a good idea if you’re keeping the existing rads.
I looked at air sourced heat pumps last year and it will be worth it for me, but I’m on oil.
I suggest you at least talk to a supplier about it, just to be sure it’s not the best option.

As an added point of interest. My grandad was a proper mechanical engineer and enjoyed messing with this sort of stuff. He Devised a ‘solar panel’ water heating system when he found this old radiator and bolted it to the roof of his garage, put some old window frames with glass in over it and then connected it to the hot water system. He reckoned the only time the boiler was needed after that was to just perk it up a bit for a bath. it was certainly hot enough to wash hands and pots in most of the time, the boiler was almost permanently off.

His only concession was that he had a valve that isolated the system which he would do at night during winter.

edit: And this was in Manchester, not tradiotnally the sunniest place on earth.

If I was installing a sytem from scratch I would deffo go down the captains road of multiple zones. Its not hard to do. along with multiple time clocks – no need for bedrooms to be heated until an hour before bedtime and so on.

Radiator stats are a pain.

Ta for all the advice so far. I’m all for more controls, but I can’t see me putting in more than three zones (we have seventeen rooms in the house), then TRVs in rooms within zones. I like the idea of adding solar coil to a system, we have a steep south facing pitched roof on a double garage adjoining the utility room where the system is likely to go, so the pipe runs for that would be short, but still be long for bathrooms and heating. No chance of going to underfloor heating, so heat pumps are out. Given the size of the place, what we’re after is efficiency to keep the bills down and good hot water flow rates to bathrooms two floors up from the boiler. Currently have a combi with built in 100l tank, but it’s ha it’s niggles and since I’m finally getting round to adding some mod cons(plaster on the wall, a ceiling etc) to the utility room now seems like a good time to swap.

Solar hot water – yep, if you have a suitable house go for it! Works very well, even bodged systems in Mid Wales provide plenty of hot water 😉

Heat Pumps – nope. Don’t like em, don’t believe the hype and by God are they expensive! If you don’t have a LARGE garden then you are getting into bore hole drilling for the installation pushing the costs up even higher… and they aren’t that efficient anyway (given that you are still using ‘leccy to heat water albeit very efficiently, but throw in the losses from generating that electric from… say… gas… then the transmission losses and you would probably be as well off burning the gas to heat the water in the first place. And better off from not shelling out the thousands for said system!)

If possible I would probably pop a dual coil hot water tank in, link one set of pipes up to a solar system and the other lot to a woodburner – generally a well designed set up should give you all the hot water you need most of the year around. The times it won’t you would want the fire on anyway 😉 The new water tanks hold heat like you would not believe (got one in the current rented house that runs on an electric immersion and it is better than I would have ever given such a thing credit for… so much so that I am already plotting a solar/biomass dual fuel system on a hot water tank for the house we are buying in a fortnight!)

We’ve got solar panels, realistically they won’t earn their money back. Our conclusion after major renovation to our house is that it’s worth investing the money instead into a very good condensing boiler, a networked thermostat system with a controller in each room, and good roof insulation.

search through CAT’s site, know they have some stuff they’ve tested up there from home made to pro and various system types

Machynlleth hippies

and I wouldn’t bother with woodchip, it’s twisting the timber market and how green is something that requires 400bhp to chip, a big shed to dry, regular turning to avoid it composting and then all the road haulage at the different stages. If you want wood stick to logs, otherwise electric or gas is probably greener.

Midlife – insulation and more insulation is probably the best you can do to improve efficiency. then add more insulation.