Very impressive "zero energy" Victorian refurb

[dan_aka_jack]

http://www.viking-house.ie/zero-energy-victorian-renovation.html

• Triple glazed windows with whole-window U-value of 0.9
• Laying UFH pipe beneath the roof tiles to capture solar heat
• 300m3 thermal store
• 300mm insulation

[KenB]

Jack,

Looks good - however I suspect the thermal store is not 300m3 

I notice elsewhere on the site a lot of good information about different external insulation techniques and a typical cost of £100 per m2 for external insulation.

Or is that £10,000? - I never could get the hang of these decimal points



Ken

[MR GUS]

Ken, list,
because I'm

A. ignorant.
B. *Having a beer or 3 on an empty stomach.

 Can anyone point me in the direction of current technique(s) for exterior insulation cladding techniques (cheers) as i've failed to find much ((admittedly useless, ..must be cos i'm middle class  allegedly))  ..I think our only way out of the current climate mess, older housing stock is being ignored & yet if you can factory make a huuf haus then you should be able to overcome the past 40 years of uk housing stock if approached & invested in seriously.

 ..Oh & could you all listen to the self depracating humour of the repeat of Radio 4's the now show (quintessential british humour) either in podcast or live format, lest we all start hurling metaphorical rockets at each other in order to level the current state of throat-ripping here! NOT this thread)
  lest we all start being accused of beardism, gingerist tendencies, anti-semite, speaking with a posh voice, walking funny, looking at my bird or whatever.
  ..be nice to one another.

*recent infuriating attitude has driven me into the brewers arms (via the fridge)

[odbob]

I like the very descriptive opposing triagles on the home page showing in very simple terms, the cost savings versus capital cost of insulation through to renewables.
I've been banging on for years about insulation being the best, whilst boring ,it is, as most people would now agree, the most efficient way of reducing energy.

[MR GUS]

They ought to teach u-values in school!  ..we might have a leg to stand on!

[wookey]

Innovative people, Viking House. They won an award recently for their polystyrene foundations (which are very good).

Now we just need a few million more renovations like that and we'll be sorted.

[knighty]

I wonder how well the underfloor heating under the roof tiles work ?

[KenB]

Wookey,

I agree with your comment

Now we just need a few million more renovations like that and we'll be sorted.

However, the likelihood is that external insulation and other eco-renovation methods will become the next "band-waggon" amongst the less that scrupulous sectors of the construction trade.  Add it to the likes of Crittal windows, pebble-dashing, stone cladding, double-glazing etc etc.

Whilst companies like Viking, clearly have a grasp of the technologies and are genuine innovators, there will be a spate of cowboy operators getting on the Green Deal home-refurbishment programme.

Viking quote approximately £100 per m2 for external insulation.  So for a 3 bed semi with about 100m2 of external wall area the cost of the external insulating process is going to be around £10K.

However, as Jack's internal refurb showed, seldom can these jobs be taken in isolation. As soon as you start investigating the structure of an older property, you find a whole can of worms.

So it might be worth considering a "package deal" - something on the lines that Viking did to the red-brick Victorian terrace. For a typical semi it might include:

1.  New roof with solar heating and "warm loft" insulation. New soffets for correct ventillation.
2.  Sub-floor insulation and UFH
3.  Party wall internal insulation - why heat the house next door?
4.  Triple glazing and better draughtproofing
5.  External insulation where applicable.
6.  Removal or blocking of any unused chimney stacks.

That level of refurb probably necessitates vacating the property for 3 to 6 months.  If the "Green Deal" offers mortgages and grants to allow the funding of such a refurb, then there may be a considerable uptake.

However if you estimate a typical green-makeover as costing say £25k, then either you need to look at very long timescales (25 years), or the cost of gas has to rise astronomically to justify that level of expenditure.

If a suburban semi is typically £200K, and you spend £25K on green refurbishment, does that automatically put it into a more desirable price bracket when and if you come to sell it?

Whatever happens in the next 5 years or so, there will be those that make a lot of money from the Green Deal, and those who are correspondingly fleeced of their savings by unscrupulous salesmen.


Ken

[martin]

Looking back at the property market's reaction to "wall cladding" in the 60's and 70's and 80's, the change in property value was firmly negative - the stuff was hyped as adding insulation, but was much sold by "foot in the door, bludgeon you into buying" salesmen largely on the totally untrue claims of "improving" the looks and adding value....
One was faced with the ludicrous situation of whole estates with traditional brick-built semis, many "halves" sprouting garish mock york-stone cladding.
The general advice in those days was "you've wasted the money you've spent, and it'll cost as much to get it removed and made good to return the property to current market value......."
In those days the standard of workmanship was generally atrocious, and cladding was well known to cause/exacerbate damp problems....... as to how much the negative views of the stuff can be overcome, and how much it has improved, I honestly don't know - I'd certainly want definitive proof of it's efficacy, and a rock-solid guarantee before embarking upon it, as well as ensuring that it is aesthetically pleasing (semis and terraces with just one property being covered looks plain daft) - and many properties are sold on "I like the look of it"..........

[dhaslam]

I wonder how well the underfloor heating under the roof tiles work ?

Not at all well unless the house actually has that 300 cubic metres of seasonal store.      The photographs seem to show something 300 times smaller.    There is no point in having  solar heating that just  heats the house when it doesn't need heat.  

A lot of their figures seem off the wall.   Standard floor insulation  losing 65% of the heat from underfloor heating for example doesn't make much  sense.     Also the cost of insulating an old house to passive  standards wouldn't leave much change from €100,000.   My new build  house cost more than  €10,000 in extras over the builders initial quote just for relatively minor changes to  insulation.  The changes were extra floor insulation, wider foundations for extra wall cavity, filling the extra wall depth and insulating the rafters.   These items were all on the plans but the builder initially quoted  for normal minimum insulation.    Compared to that the solar heating system and  seasonal store that should be completed shortly for about €2000 it dosen't make financial sense.  The solar heating system would have  needed to be doubled in size if  the  extra  insulation  wasn't installed.    The running costs with extra  solar heating  would be higher  but a few PV panels would take care of that, or in my case a wind generator.  

What it means is that you have to be sensible about insulation and realistically compare the cost of  additional heating with extra insulation.  

[KenB]

I guess its a case of weighing up the potential energy savings against the cost of the refurbishment.

I currently use 15000kWh of gas in a typical year - it costs me almost £500.  At 150kWh/m2 this property is the sort that is "ripe for refurbishment"  - it's just a matter of financing the improvements.

Let's suppose that gas shows a similar price rise as it has done in the last decade. It's now 250% of what it was in 2000.  This is not an unreasonable first guess of future price prediction, however there could be energy price shocks, wars, consumption growth of developing countries  and a whole host of other reasons (greedy bankers) that manipulate the gas price.

By 2020 it could be 8.0p/kWh and by 2030 it could be 20p/kWh

Suppose I borrow £25K at typical mortgage rates on a 20 year term.  It will cost me about £220 per month for 240 payments.  A total of  £52,800.

If my £25K of green refurbishment, cuts my gas consumption in half, based on a 250% rise in gas cost per decade - my savings each decade on my gas bill will be:

2010-2020   £2500
2020-2030   £6000
2030-2040   £15000
2040-2050   £37500

It's only between 2040 and 2050, when gas is 50p per kWh where I will actually save enough on energy costs to recoup what I paid out on the refurbishment.

So the above illustration suggests that you have to be looking at the very long term (40 years), and there has to be a large increase in gas price from decade to decade in order to find financial justification for the upgrade.

I also chose to use only a 50% reduction in gas consumption as a result of the refurb.  It could be more, depending on the final U values of the insulated walls, roof and floors - and how much contribution to heating that the solar panels contribute. 

Under the Renewable Heat Initiative, you could get 20p/kWh for solar heating systems, and if you install pV as well, then payments received under FITs will help offset the cost of financing the system.  http://www.rhincentive.co.uk/eligible/levels/

However, not all decisions are made in terms of finance alone, and there is a likelihood that if you live in a 100 year old semi which was last upgraded in 1960 - then it's well overdue for another refurbishment, and the cost of the refurb can be justified in that you had to replace the roof, the heating system and the double glazing anyway.



Ken
 

[dhaslam]

But would you use gas at 50p per kWh anyway?     The big  change that has to come is  production of electricity  from renewable resources.   It has to have massive resources put into it in the next decade.   As somebody said "world war two with everyone on the same side".   However no one  seems to want to fire the first shot.     

[KenB]

Dhaslam,

I was trying to illustrate a possible scenario, which may or may not occur.

So long as there is a supply of gas, our utilities will continue to use it for power generation, and make it available for space heating.

If we ever reach 50p/kWh by 2050 then there will probably be other things to worry about. 

What I'm questioning is whether spending 10% of my income, for the next 20 years, until I'm 65, paying a Green Deal mortgage on an eco-refurb is going to be a good, and essential investment? 

If it is common sense for me to embark on this strategy - then it probably makes sense for every other 30/40 something who has been forced into low grade, low energy efficiency housing - because of the state of the housing market in the last decade.

Wookey quoted that the reduction in domestic energy usage could be as much as 80%, with the right mix of external insulation and solar heating. If this is the case, it would be good to see case studies that illustrate that these rates of energy efficiency improvement are achievable - then it puts a completely different emphasis on the calculations.



Ken

[wookey]

That 80% came from the example house in the 'great British Refurb'. http://www.greatbritishrefurb.co.uk/will+homoky/ That cost £23K for materials, including £12K of PV. Labour was provided as sponsonship in this case and thus not included, which isn;t very ehlpful for doing these sums. In general I reckon a ballpark of £20K per building gives the right idea.

Ken, I would hope that the 'pay as you save' scheme proposed in March would help with your numbers, but your general point remains valid. I do think that a shift in how people view the efficiency of a house is likely to take place over the next 10 years, and it really will start to matter to people (and thus become worth something). Relatively small changes in property prices can dwarf all the other considerations financially. If I'm right then that'll pay for the upgrades automagically, and in fact it'll be like PV and you'll be pleased to have started now and beaten the rush.

Doing it DIY of course is excellent value. More like 2K to insulate your house, another few for everything else. But it will take you bloody ages. We've spent about £5K here for loft insulation, internal wall insulation, boiler, woodburner, solar thermal, airtightness, new door. Probably need 2-4 more for MHRV, floor insulation, block up spare chimney. And then there was £13K for PV which is a bit of an outlier.

[Amy]

Wookey

The payback view that most people focus on is I think shortsighted.
20 yrs ago I was living in a bungalow that was originally a timber frame, timber clad building. The cladding rotted away and was replaced by a 4.5'' brick skin, leaving a 10'' cavity with no bottom to it and a suspended floor void of 2'

on windy days, the carpets would lift and the wind blew in through the electric sockets and light switches.

I was limited as to what insulation I could apply, so I battened the plasterboard walls, added 20mm of jabalite and 1/2 of plasterboard on top. I also reboarded the floors.

Thermally, not much progress but cutting down on the draughts made a huge difference to the comfort levels.

So, payback wasnt just about energy saved but also comfort gained. I would think that after the winter weve just had, having a house thats comfortably warm throughout is another valuable gain thats just as important as money saved.