Renovating and want to change from oil, but to what????

murphydog999

We need help, this is a minefield of a subject!! Sorry it might be long.

We are about to start the renovation of a house not long bought. Part of it was 3 cottages - approx 200 years old - (knocked into one obviously) plus a 1980's double extension tacked onto the end. It has little or no insulation and the central heating has cost us £600 in oil for 2 months!! (heating on 6 hrs per day) I won't go into the inefficient heating system, it's uncontrollable and pants! We are rural (so no gas) and detached and approx 300m2.

We will be changing the roof, windows, moving walls, it's a big job, so it makes sense to change the heating system while we are at it. (We are told that the worcester bosch boiler is only 7/8 years old though.)

We will be addressing the insulation issues (I'll come onto this in a sec) with external, as we will be partially cladding and rendering. The problem is finding something suitable (pref. renewable) for this type of property. We have the outside space for a GRHP system - but we want something controllable rather than a constant low-heat - we have a plenty of south facing roof for a PV system; what else is there for our circumstance?

Back to insulation. We had a 'green deal' surveyor round today who told us that unless we have either roof insulation or cavity wall fitted by the end of the month we won't qualify for the freebie.

Well, this is too soon for us, but he told us that a new deal was being announced in March where 85-90% of the cost of any surveyor recommended solutions will be covered. No loans, no nothing, £890 million put aside plus the same again from the utility companies. This is nothing like the current terms listed on the green deal internet site, so we don't know who to believe. Obviously we hope he's right (he did say they are all being trained up for it now, so we have no reason to doubt him) it would save us a fortune.

Anyhow, I would really appreciate any 'what about...........' or 'have you thought about...........' or any little gems of inspiration anyone might care to add.

Many thanks, Murph

reeac

murphydog999 wrote: »

We need help, this is a minefield of a subject!! Sorry it might be long.

We are about to start the renovation of a house not long bought. Part of it was 3 cottages - approx 200 years old - (knocked into one obviously) plus a 1980's double extension tacked onto the end. It has little or no insulation and the central heating has cost us £600 in oil for 2 months!! (heating on 6 hrs per day) I won't go into the inefficient heating system, it's uncontrollable and pants! We are rural (so no gas) and detached and approx 300m2.

We will be changing the roof, windows, moving walls, it's a big job, so it makes sense to change the heating system while we are at it. (We are told that the worcester bosch boiler is only 7/8 years old though.)

We will be addressing the insulation issues (I'll come onto this in a sec) with external, as we will be partially cladding and rendering. The problem is finding something suitable (pref. renewable) for this type of property. We have the outside space for a GRHP system - but we want something controllable rather than a constant low-heat - we have a plenty of south facing roof for a PV system; what else is there for our circumstance?

Back to insulation. We had a 'green deal' surveyor round today who told us that unless we have either roof insulation or cavity wall fitted by the end of the month we won't qualify for the freebie.

Well, this is too soon for us, but he told us that a new deal was being announced in March where 85-90% of the cost of any surveyor recommended solutions will be covered. No loans, no nothing, £890 million put aside plus the same again from the utility companies. This is nothing like the current terms listed on the green deal internet site, so we don't know who to believe. Obviously we hope he's right (he did say they are all being trained up for it now, so we have no reason to doubt him) it would save us a fortune.

Anyhow, I would really appreciate any 'what about...........' or 'have you thought about...........' or any little gems of inspiration anyone might care to add.

Many thanks, Murph

Not an easy one! Firstly insulation: roof easy, windows easy but walls [presumably solid] not easy as internal added on insulation might encroach on living space unacceptably. Same with floor insulation.
Secondly fuel: it's oil, electricity [direct or heat pump], solid or solar. Being rural maybe you have easy access to timber? Solar would only be of minor assistance.

The forum would need more details in otder to comment more fully.

[Deleted User]

As you are off mains gas your choice is basically electric, oil and LPG. For conventional heating systems oil is your best bet.

But surely once you renovate and insulate your oil bills will be much less, but at the end of the day it is a large old house so will never be cheap to heat like a modern property...

If you have the funds then stoves are a must for cosy nights and heating when there are power cuts. Consider PV and do some calcs to see if it works for you. Depending on DHW setup also consider Solar Thermal/Immersun device to reduce oil usage.

As for renewables have you considered biomass boilers for controllable heat?

TiredGeek

£600 in oil in two months... roughly a tenner a day.....
For a 300m2 old house I don't think that's bad. I'm not taking the p, I really don't think it's too bad.

You'll have to be VERY carefull with exterior insulation on such a building, get a second and preferably a third opinion as you may cause significant damp problems in the walls.
A 200 yr old house won't have a DPC and moisture wicks up into the stone and then evaporates away under normal circumstances, both inside and outside of the house.
If you put anything on those walls that is impervious then you trap that water in there.
At best you'll end up with damp patches inside the house, at worst the damp will cause the lime mortar to degrade and the walls will fall down!

I'd get advice from a "heritage" structural engineer who understands old buildings before committing to anything, particularly something recommended by someone with a vested interest

Oil has it's advantages if you're wanting quickly controlable heating but is gonna cost more if you run it for long periods than either ASHP or GSHP, but they cost more to fit in the first place. If you only want to run it a couple of hours a day then it may end up cheaper in the long run.

murphydog999

TiredGeek wrote: »

£600 in oil in two months... roughly a tenner a day.....
For a 300m2 old house I don't think that's bad. I'm not taking the p, I really don't think it's too bad.

You'll have to be VERY carefull with exterior insulation on such a building, get a second and preferably a third opinion as you may cause significant damp problems in the walls.
A 200 yr old house won't have a DPC and moisture wicks up into the stone and then evaporates away under normal circumstances, both inside and outside of the house.
If you put anything on those walls that is impervious then you trap that water in there.
At best you'll end up with damp patches inside the house, at worst the damp will cause the lime mortar to degrade and the walls will fall down!

I'd get advice from a "heritage" structural engineer who understands old buildings before committing to anything, particularly something recommended by someone with a vested interest

Oil has it's advantages if you're wanting quickly controlable heating but is gonna cost more if you run it for long periods than either ASHP or GSHP, but they cost more to fit in the first place. If you only want to run it a couple of hours a day then it may end up cheaper in the long run.

Thanks for pointing this out. We have been searching for a leak in the system we couldn't believe it had gone down so quickly!

The green deal surveyor mentioned there has been a big programme of external insulation work (with very good german render) on hundreds of single skin houses locally. I don't disagree with your comments at all, but is all this work being done only to cause more problems down the line? Or is it the age of our house that's the problem?

The house is currently rendered and we were looking at a partial timber cladding. The 1980's extension part is cavity wall, presumably external insulation wouldn't be a problem with this?

muckybutt

You could look at renewable heating such as a gasification boiler if you have access to free or cheap wood, or alternatively a large pellet boiler with hopper.

Both these systems if installed by a MCS acredited firm would get you a grant which would pay out for the next 5 years

TiredGeek

murphydog999 wrote: »

The green deal surveyor mentioned there has been a big programme of external insulation work (with very good german render) on hundreds of single skin houses locally. I don't disagree with your comments at all, but is all this work being done only to cause more problems down the line? Or is it the age of our house that's the problem?

The house is currently rendered and we were looking at a partial timber cladding. The 1980's extension part is cavity wall, presumably external insulation wouldn't be a problem with this?

There are likely to be big problems in ten years or so (maybe less) for people with solid walls and this sort of thing. It's been mentioned a few times on renovation programs on tv and having an old house with metre thick solid walls I picked up on it and looked into it a bit deeper.

The structural issue comes from the fact that 100+ year old houses were built with lime mortar, not the newer cement based stuff. Lime mortar never fully dries out and remains flexible which allows the walls to move slightly without cracking and is porous like the stone itself.
Moisture in the air and from the ground permeates the stone and mortar, if it can evaporate away then there's no problems. If it's trapped in there, say by insulation or modern cement render then the lime mortar degrades. If you're in a moist environment (heavy rain area, boggy ground etc) or the wall is sealed on both sides, then the degradation will be faster. In the end the mortar cannot hold the walls together and they could even collapse!
You'll also get more moisture inside the house if it can evaporate in that direction, and more than likely cold damp walls.

A more modern wall, with a cavity will have a DPC to stop moisture rising from the ground and you'll get minimal moisture from rain. What moisture does get into the wall evaporates inside the cavity as well as the outer surface so the inner wall stays bone dry anyway.
This is also a ticking bomb for those with cavities and moisture retentive blown cavity insulation - any water that makes it through the outer skin doesn't evaporate and eventually you have porridge inside your walls which you can't get out and will make the inner walls wet and cold too....

You mention your place is rendered, is it a non porous (after about WW1) cement based or just a thick lime wash? If it's been done for over a hundred years it'll probably be lime wash and it's fine, cement based and it's trapping water

I can't say for certain about the insulation and render in question, you'd need a "proper" independent surveyor who is working for you and doesn't have a stake in the product so won't be biased for profit.
It might be absolutely fine for your house and all those around you, then again it might not show up for years that there's a problem.

It sounds like you plan to spend many thousands on the place, maybe another grand or so for a heritage type surveyor to assess your current structure and look over your plans with an eye to insulating might be a wise investment and save you a bucket load in the long run....
I assume you have some sort of architect on board to do drawings etc, pose the question to them, if they don't know they may know someone who will

The good thing about solid walls is the heat retention, once you've got them warm they tend to stop the peaks and troughs you get with "normal" walls. It's called thermal lag, when your heating goes off the air in a normal house cools quite quickly, your walls will retain the heat better and release it back into the house which keeps you warmer for longer. They'll also keep you cool in summer

Have a google, there's plenty of info out there

murphydog999

TiredGeek wrote: »

Have a google, there's plenty of info out there

This is the problem!

My neighbours family used to live here years ago, I've left him a message to see if he can remember when the render went on. But I'm sure it is over 12 years ago and under 50 years, as he has a picture of it in the 1960's.

There are no damp/condensation issues anywhere, except on an end wall there is one small patch in a downstairs loo, and ironically that wall isn't rendered! It's def. not lime render, so I would have thought we would have some issues?

I've never heard of a gasification boiler, but Biomass looks interesting.........

TiredGeek

murphydog999 wrote: »

There are no damp/condensation issues anywhere, except on an end wall there is one small patch in a downstairs loo, and ironically that wall isn't rendered! It's def. not lime render, so I would have thought we would have some issues?

Sounds like you're doing well then
It could be that because the house is kept warm and (probably) drafty that any moisture in the walls is evaporating away internally without causing signs of damp.
It may be that the ground around your house is relatively dry so there's not much water to wick into the wall in the first place...

I'd still get it checked out before spending a shed load of money on the place

murphydog999

Yes, there are quite a few drafts, and being in Worcestershire, fairly close to the Avon and the Severn we are not short of a drop of water! We have a very full well, a lake and we are on clay!!!

Pansy_Potter

We went through a similar process on choosing a new heating system for our house renovation recently. I was going to have biomass automatic feed wood pellet boiler but gave up eventually as it was going to be too costly to purchase. In the end I opted for oil, which we use as low background heat with woodburning stove in the room we use most. If you are worried about the "green" aspect of oil I was advised that it is very possible to adjust the burners on oil boilers to run on bio fuel. Only problem was I can't get a supply of bio fuel in my area yet. If you have a ready supply of used chip oil it is possible to process yourself if you have the will and ability to do this!! Good Luck... PS The adjust ment is also possible to use Red Diesel if you have this - apparently cheap but definitely not eco friendly!!