Replace a one-pipe heating and water system - worth it?

What_time_is_it

Hi. We are considering options for upgrading an old heating system in my Mother-in-law's house. It is a old one-pipe system with a 40 year old boiler and water tank. The house is very large and she lives on her own. The insulation is very poor and the windows are single glazed and leaky. Obviously her fuel usage is very high - around 60,000 kwhs on gas over a year. 

What are our best options? We don't want to break the bank and things like proper insulations and double glazing would cost too much.
We are considering the following 2 options:

1. Replace just the boiler and water tank? (maybe about £3k?)
2. Replace the whole pipe system with a two-pipe set up and get a new boiler and water tank? (we've been quoted about £15k for this)

She also has no showers in the house (only a large old bath) and her decreasing mobility means that we will need to refit her bathroom too.

All opinions and tips would be very welcome.
Thanks.

NSG666

Worth looking into whether she is she eligible for any grants?
At 40 yr old the boiler will be very inefficient so worth replacing. As she lives alone then look at a combi boiler so she's only paying to heat water as she uses it.
Get trv's on the radiators and set them so rooms not used are just kept aired.
Don't change the one pipe system - better spending the money on insulation.

What_time_is_it

Thanks. We were told that a combi boiler won't work so it will have to be a standard boiler.
Similar with TRVs - we were told that they won't work on a one-pipe radiator system.
And with replacing just the boiler - we've been told that this will improve efficiency, but not by very much at all if we connect it up to the old one-pipe system.

What insulation would you have in mind? The only thing we can really think of is maybe loft insulation in part of the house and perhaps some rudimentary DIY double glazing. It is a very old and very large house so our options for insulation are limited.

FreeBear

I doubt you will get a simple boiler+tank replacement for £3K.

Replacing the current heating system with a two pipe set up will make better use of the heat being generated. Planned carefully, you should be able to reduce pipe runs to a minimum - Just make sure you oversize the radiators. Fit an electric shower (can highly recommend a thermostatic one such as the Triton T80+, not cheap though), and you won't need to worry about keeping a tank full of water heated all the time.

Doing a simple boiler swap or fitting a new heating system isn't going to save a huge amount of energy unless the property is also upgraded. Plugging drafts and boosting loft insulation are both low cost and can make a big difference. If funds don't allow for replacing all the windows & doors in one go, just do a few rooms at a time - It is what I've been doing here, and it has made an incremental difference in comfort levels.

Ultimately, a large house with a single occupant is not "best use of resources" - Perhaps persuading her to sell and move to a smaller, better insulated/heated property would be a better long term option.

What_time_is_it

Thanks @FreeBear.
The electric shower options sounds like an excellent idea. Although, to be honest, the water and the heating are both on all of the time over winter anyway! Can't have the heating on without also heating the water, so the water is like molten lead during winter!

grumbler

If the house is purely insulated and leaky, the only way to reduce the costs noticeably is to insulate it in the first place.

How big is the house? Make improvements in the main room(s), replace some windows and stop heating the whole house. The latter may require some changes to the heating system.

FreeBear

What_time_is_it said: Can't have the heating on without also heating the water, so the water is like molten lead during winter!

A zone valve & tank thermostat will help there. If you haven't done so already, TRVs on the all radiators is also worthwhile - Any unused rooms, turn the TRV down to frost setting, shut the doors, and then you are not wasting energy heating unused spaces. Just be mindful that condensation will be a problem in these rooms so they will need airing from time to time.

What_time_is_it

The house is very big - 3 story detached house with 7 bedrooms and 2 bathrooms. All original fixtures and fittings from the 1920s. 

Really it comes down to weighing up what will actually save money. She wants to stay in the house but we don't want to throw money at it for no reason.

The house will be left to her two children when she passes away and they will not be able to afford to keep it (inheritance taxes will be very high) and certainly can't afford to live it (energy bills, council tax, etc, are through the roof). So it's a case of what do we spend money on now to make the house warmer and more efficient.

grumbler

What_time_is_it said:

The house is very big - 3 story detached house with 7 bedrooms and 2 bathrooms.

3-storey house with bad windows acts like chimney when you heat it.

Is there a door to the top floor?.

What_time_is_it

grumbler said:

What_time_is_it said:

The house is very big - 3 story detached house with 7 bedrooms and 2 bathrooms.

3-storey house with bad windows acts like chimney when you heat it.

Is there a door to the top floor?.

No. It's an open staircase to the top floor landing. Basically on open 3 story staircase linking the hall and entrance area to the landings on floors 2 and 3. There are 2 bedrooms there which both have doors which are kept closed. Insulation is pretty much non-existent and windows are from the 1920s.

Bendy_House

Hi Wtii.

What boiler does she currently have? I'm guessing it's a large floor-standing job?

Since you cannot afford to do this 'properly' - ie insulate, double-glaze, change heating system, etc. - then I'd agree with the previous advice; do these things ONLY to the rooms she actually needs. Ie, a living area, a bedroom, the kitchen, a bathroom. And shut off the heating completely in all other rooms (unless there's an actual risk of frost damage!).

An unheated room will be fine, even over winter, PROVIDED it is kept ventilated (windows on vent or ajar) and the door to the house is shut (so no moist warm air from the 'living' parts of the house get in there).

Choose the best bedroom for her, ideally one with an en-suite or close to a loo. Any chance this can be moved to the ground floor for winter?

Ie, try and get the living areas close together. Now draught-proof, insulate if possible, and definitely double-glaze these rooms.

A one-pipe system really requires a hot delivery temp, so that the last rads on the run don't lose out. But, with every other rad shut off, this should cut her fuel bills dramatically (IF she is currently heating the whole house.)

TRVs should work ok on a one-pipe system, but the issue is that they tend to be a bit restrictive to flow, and one-pipe relies on an easy transfer to the rad. Even ordinary valves should be 'full-bore', very rare these days. So perhaps just shut down all the rads that aren't needed, leaving them literally luke-warm. And, if there's no risk of freezing, fully shut off.