Heating and hot water dilemma

number22

2 years ago I installed a solid fuel back boiler stove in an old house I was doing up. After 2 winters I’ve come to the conclusion I need to upgrade as it heats the radiators and the hot water cylinder, but not really both at the same time effectively. I also have 3 storage heaters on NSH rate providing heat in the mornings and before the stove is lit, but they are very expensive to run. As well as a new shower running from the cylinder, I have an electric shower which is currently the only heat I have in the summer as I don’t really use the immersion heater to keep my electricity bill down.

I’m not on mains gas and looking at either keeping my hot water cylinder and installing an oil boiler, or getting rid of the cylinder, giving me more space that I could do with, and getting an oil combi and tank, or gas combi and tank. I do have outside space for an oil or gas tank, and I’d put either oil boiler outside, whilst a gas combi would have to go inside (where space is tight) unless I can build an insulated box or cabinet on an outside wall that wouldn’t invalidate a warranty.

Each option is going to be very disruptive and from what I can see, take years for the saving in running costs to cover the installation costs, but I do have 2 questions I’ve not been able to get definitive answers to:

1 Do oil combi boilers work exactly the same as gas combis regarding water flow and temperature, specifically, can you spend an hour in the shower with the same constant temperature and flow rate throughout (unless someone turns another tap on which takes the hot water away with a gas combi). I believe oil combis have internal water tanks and specs refer to ‘recovery time’, does that mean you will be standing in the shower with cold water until the tank reheats?

2 I want to keep my back boiler and use it to heat only my radiators, get rid of my storage heaters, and use the gas or oil boiler for hot water and for a few hours a day for supplementary heat. If I go for either combi boiler, will it be compatible with my back boiler heating the radiators only, or could I have overheating or other problems?


Would appreciate any answers, or any other advice at all anyone can offer on my options.

Calahonda52

What is the hot water demand profile in the house?

If it were my gaff, unless you have free solid fuel, I would lose the back-boiler end of the stove and get a stand alone one if you want.


Go either gas or oil: depending on your location, oil is prone to theft while LPG tankers can't travel in frosty weather to the same extent as oil tankers.
Make you gaff as airtight as possible with good controlled ventilation and well insulated

number22

Thanks for the reply and comments Calahonda. it's myself plus 2 kids about 1/3 of the time only so not huge and insulation etc is good. I'm reluctant to lose the stove altogether and it's an inset and would be a major job to remove. Do you know anything about oil combis or compatibility?

Dtp1979

number22 wrote: »

Thanks for the reply and comments Calahonda. it's myself plus 2 kids about 1/3 of the time only so not huge and insulation etc is good. I'm reluctant to lose the stove altogether and it's an inset and would be a major job to remove. Do you know anything about oil combis or compatibility?

Combis are only suitable if you have 1 bathroom. Ideally in apartments in England where they have fantastic water mains pressure.
You can't have a stove heat rads only as it needs a heat sink .ie, cylinder.
As for a gas Boiler, have a local rgi on site to discuss location of install

number22

Thanks for that but do you mean gas or oil combis? I've had gas combis in the UK so familiar with them and I had a gas installer look at my system for a gas combi a while back and he din't indicate it would be a problem not having the cylinder, perhaps there is a way around it? re water pressure, I have 12 litres per minute mains to my house and it seems that I won't get any more than that in the shower, and maybe a bit less from a gas combi as they won't go higher than the mains flow rate in, but I should still get better than the 8 litres per minute I'm currently getting from my shower with a 2.6 bar pump (that I'd have to lose with a gas combi), which as actually quite a good shower, particulary as almost all have flow rates above 10 and many much higher.

Oil combi is looking like cheapest and best option overall, despite high cost of boiler, but I have no experience of them, do you or anyone have one or know if constant flow and pressure of hot water is guaranteed as same with a gas combi?