Thermal Mass in an older property - observations on heating

[KenB]

Rupert,

No problem - I was perhaps a bit quick to comment.

The point is that energy is still very very cheap compared to the rest of our financial committments.

To do a worthwhile job of insulating this place would probably cost £10k, and the amount saved might be £100 per year.

Conversely, if i borrowed £15K and installed a 3kW pV system, FITs would pay me about £1000 a year.

I'm stuck between a rock and a hard place.



Ken

[Billy]

Hmmmmm.

not in my case.

No cheap gas, electric intermittent, not much forest, oil - horrendous and not much left!  Cheap energy would be brilliant if I could get hold of any!

"Rock and a hard place", if only.

No mortgage. no utilities, no nothing, but it's not easy, maybe it would be easier getting a proper job and having some services.

Camillitech is getting old, will it get worse, will I soon be too old to collect the driftwood to keep warm and (therefore) die?

Winter fuel payments, what is that?

Billy

 

[StBarnabas]

Billy
don't forget Camilitech's trained "slaves!" He'll be fine if he can keep them on the island.....

[Rupert]

Well £10,000 and you save just £100 per year and in 20 years you would see just £2000 of your money back. If fuel prices quadraupled tomorrow morning you still wouldnt see a return on your investment in 20 years!!.....Ever think that all this energy stuff  could be a waste of time?

[dhaslam]

If you have a place to put a  hot air panel, costs  a few hundred pounds and  in sunny frosty weather you get hot air at 80C.   I was getting  just 80C  today and each panel has a fan  moving  over 200 cubic metres of air per hour, that should be about 4 kW output each.   The Navitron ones are smaller   but would produce some heat in dull weather as well   and  you just need a south facing wall with a room inside that needs heat.         

[Billy]

Rup,

Yes,   

Billy

 

[billi]

Dhaslam is right 

Trombe  as well http://en.wikipedia.org/wiki/Trombe_wall

If i would have a wall  facing south  and as thick , i would glaze it ( make a collector of the whole )  instead of insulating it and render

Billi

[wookey]

Ken, if you insulate your house properly it could cost more than 10 grand (unless you DIY, in which case it'll cost less than half of that), but it should also save you a lot more than 100/yr. You should be able to halve losses and get your bill down to 300/yr. but perhaps more importantly it shouldn't be just about the money. People, especially people who understand about energy use and EROI, should be embarassed to be living in a house without wall insulation and a plan to minimise thermal bridging. You know perfectly well that that energy price is articifially low because very little of the CO2 cost is priced in currently, and that energy prices are likely to continue rising steeply over the next 20 years, and that the house is going to keep using energy for maybe 100 years. As current owner is falls to you to do somthing about that. We have 14 million solid-walled houses that need insulating in the next decade - that's 1600/hr which is an awful lot of work...

Some govt incentives to help people get over the retro-fit cost hump would be very helpful and incredibly cost-effective. The details of such a scheme have not yet been announced, but things are looking promising. GBP 6000/household is intended to be made available: http://www.greatbritishrefurb.co.uk/minister-says-green-deal-is-for-everybody

First there will be incentives, and encouragements, and finally sticks for the recalcitrant. You don't want to be left at the end when the incentives are gone and your house is condemned for low insulation levels.

[KenB]

Wookey,

Of course it is preferable to live in a well insulated house, and since the insulation work is a major undertaking, it is best to incorporate it with other rennovation work, to keep disruption to a minimum.

In my own case, I have been holding back with such work, so that I can incorporate it with replacing the roof, which will need scaffolding, converting the loft and doing a major renovation to all upstairs rooms - new plaster, new ceilings etc.

As this represents some 4 months work with a professional builder, and most likely, temporary accommodation elsewhere - it is not something that can be undertaken without considerable planning and expenditure.

Thankyou for pointing out the greatbritisrefurb scheme - hopefully there will be money made available - and this will not be yet another greenwash initiative which leads to nothing.

In the meantime, I think that there is value in documenting my work, and studying the heatloss in older properties - because there are millions of properties like mine - and a before and after study might be very informative.

I have made some inroads into improving energy efficiency.  The loft was insulated in October 2000, a new boiler and underfloor heating in 2005, and a refurbed kitchen bathroom in 2005 which effectively brought the whole of the back of the house up to current insulation requirements.

The attached shows the improvements in gas consumption over the last 9 years.  A minimum was reached in 2007 - less than half the 2001 figure,  due to favourable weather, and a concerted effort to minimise. 

However, there is only so much that can be done easily with an older property - and soon you are into the territory of diminishing returns.


Ken

[KenB]

The plots of room temperature from Thursday night showed a heat loss of about 3 degrees in 4 hours, when the outside temperature was between -1C and -2C.

These plots were for Sunday 25th October, showing the cool down from 8am to 4pm.   During that time the outside temperature rose from around 2C to about 9C.

Here the heat loss is approximately 1.5 degrees in the first 4 hours - which is half of the rate of the frosty night.

Also shown is the temperature difference Delta -T , between inside and outside temperatures.  Note that during the course of the morning and afternoon as the outside temperature rises, the value of delta T can almost half.  By measuring Tin and Tout, and calculating delta T, the controller can estimate what the heat loss to the outside is - and compensate for it.

On a relatively mild night, the heating could be turned off at midnight, and coast down to around 17C at 6am,  on frosty nights a top up from the boiler would be needed about twice.


Ken