Is external insulation worth it?

Shelca

‘70’s detached, cavity-block. Bits and pieces done over the years, double-glazing, roof insulation, some bits of internal insulation. Recently rated E2. The high-efficiency boiler/heating controls package will bring it to D1 and external insulation in addition, to C1.

I’m going ahead with the first option but not sure about the insulation. The payback period is claimed to be 10/11 years but my annual bills (gas + electricity) = €1,400, are only one-tenth of the cost of installing. No payback at all unless energy costs soar. The annual costs are manageable and the house is quite comfortable as is.

The only other way I can think of looking at it, is as an investment. The money placed on deposit would yield €340 p.a. and I’ll still have the capital. I’d need to see the bills reduced by at least that amount and at the same time expect that the house’s value will increase by the equivalent of the capital. Are these realistic expectations?

What about the idea that it can be expected that neighbours will eventually begin to seek to improve their ratings and I’ll at least remain competitive? OTOH, there’d be no need to do that unless and until I decided to sell. It’s a puzzle!

MicktheMan

Shelca wrote: »

‘70’s detached, cavity-block. Bits and pieces done over the years, double-glazing, roof insulation, some bits of internal insulation. Recently rated E2. The high-efficiency boiler/heating controls package will bring it to D1 and external insulation in addition, to C1.

I’m going ahead with the first option but not sure about the insulation. The payback period is claimed to be 10/11 years but my annual bills (gas + electricity) = €1,400, are only one-tenth of the cost of installing. No payback at all unless energy costs soar. The annual costs are manageable and the house is quite comfortable as is.

The only other way I can think of looking at it, is as an investment. The money placed on deposit would yield €340 p.a. and I’ll still have the capital. I’d need to see the bills reduced by at least that amount and at the same time expect that the house’s value will increase by the equivalent of the capital. Are these realistic expectations?

What about the idea that it can be expected that neighbours will eventually begin to seek to improve their ratings and I’ll at least remain competitive? OTOH, there’d be no need to do that unless and until I decided to sell. It’s a puzzle!

Just doing some back of the envelope calculations based on the info you gave.

House rating E2 => 340 kWh/m2/yr @ 6cent per kWhr = Eur20 per m2. Your annual fuel bill is eur 1400 so your house size is approx 70m2! Is this correct? Note I have not included any fuel for DHW.
(Now, I know people are going top point out to me that the rating is an asset rating and is independent of individual behaviour but the OP states that the house is quite comfortable as it is.)
Do you have an open fire/stove. If so, what fuel do you burn in it and how much per year? Have you included this cost in your calcs?

When doing you calcs make sure you have factored in the effect of inflation on the real value of money.

Suppose you were to borrow 14000 euro at 5% interest to halve your current energy consumption and assume average inflation of 2% with energy inflation at 7%.
If you were to use only what you saved on energy to pay back the loan, then it would take 17 years to repay the loan. Thus not costing you a cent or any capital! Now in year 18 if you hadn't done any energy improvement work your energy bill would be over 3200 in todays money!
Now, if you put the 14000 on deposit at 5% for the same length of time and did not touch it, you would receive a interest payment in year 18 of 674 euros in todays money.

It is clear to me that an investment today in improving the energy efficiency of your home is one of the most secure and rewarding investments you can make.
Caveat:
the advice and work (workmanship) you receive and get done is up to the job and will deliver the energy savings promised.

Shelca

MicktheMan wrote: »

Just doing some back of the envelope calculations based on the info you gave.

That's extremely interesting - and impressive as well!

House size
Conventional 1500 sq ft 2-storey.

Open fire
None

Effect of insulation
Are you quite comfortable with halving the gas costs? I should explain that the €1400 I used is made up of Gas €900 and Electric €500. We run an immersion heater at present when the heating is off - say 3 months at 45 min per day on 'Sink' setting. A new hot-water tank is to be installed so I expect to discontinue the use of the immersion heater, meaning that the gas bill will increase somewhat. I suppose that €1,000 could be used for simplicity.

Loan
You are obviously experienced with the calculations. Did you find the annual cost of repaying the loan to be c. €1,200?

Any effect on your conclusions due to anything above?

Many thanks. I appreciate your help.

MicktheMan

Shelca wrote: »

Effect of insulation
Are you quite comfortable with halving the gas costs?

Not at all! I took a reduction in energy use by 50% from you (BER going from an E2 to C1).

My point really is that if you can achieve a significant energy reduction by f.i. installing external insulation, then the figures show that the financing of it is in general a no brainer.
The real challange is to
1) ensure that you know where you are really wasting energy
2) quantify this wastage
3) ensure that the remedial work carried out addresses this wastage
4) ensure that the lifespan of the remedial work is longer than the payback time, at least 25% longer.

For 3) above, going on what the sales man tells you doesn't cut it. Get independent advice here.

Note also that in most cases the actual savings will be lower than expected as some of the savings will be absorbed in much improved comfort levels.

holdfast

try doing them cals on a stamp mick hope things are going well in clon.

back to the topic external insualtion is better than internal. Reduces thermal bridging, prevents damp pentration, revamps the external of the build giving a new look to the build and you dont have to move out. I would also look at the other alternatives to improve your rating. From working on the HESS orginal trial scheme there could be a number of other options that your assessor could recommend. As the extra cost may not be as much if you group the work into one contract. Such as up grading heating controls and boiler, installation of stove or the addition of a draught lobby.

Shelca

MicktheMan wrote: »

Not at all! I took a reduction in energy use by 50% from you (BER going from an E2 to C1).

You'll have to excuse my ignorance! I didn't know how it was calculated. The heating package brings it from E2 to D1 and the insulation supposedly brings it from D1 to C1. What percentage is the latter, can I ask?

MicktheMan

Shelca wrote: »

You'll have to excuse my ignorance! quote]

I assumed you were aware of what the different bands meant. This should have been fully explained by your BER assessor!

As you will see on your cert "D1" is between 225 and 259 kWh/m2/yr and "C1" is between 150 and 174 kWh/m2/yr. As the cost for the boiler/control upgrade would be considerably less than external insulation, the bigger bang for your energy buck would be to first invest in the boiler/control upgrade.

Why havent you asked your BER assessor these questions?

Shelca

MicktheMan wrote: »

Shelca wrote: »

You'll have to excuse my ignorance! quote]

I assumed you were aware of what the different bands meant. This should have been fully explained by your BER assessor!

As you will see on your cert "D1" is between 225 and 259 kWh/m2/yr and "C1" is between 150 and 174 kWh/m2/yr. As the cost for the boiler/control upgrade would be considerably less than external insulation, the bigger bang for your energy buck would be to first invest in the boiler/control upgrade.

Why havent you asked your BER assessor these questions?

He's on holidays. However now that with your help I have a much better understanding of the subject, I'm much better prepared for when I meet him next week.

Thanks again. It's appreciated.

SilverBER

In fairness, there are quite a few BER assessors who would not be comfortable with this kind of stuff. There are grants available for everything you mention below including the before and after BER. Has anyone done any business with the greenloan HES scheme? From my understanding of it it seems to be beneficial in that the work is checked when it is completed, unlike other schemes that I know of.

legs_akimbo

External insulation of only one make is being allowed for use in the SEI scheme, a change recently implemented which would preclude any firms familiar with using different materials and work practices...ensure any proposed works are using sei accredited materials or you will not be reimbursed by sei even if the contractors are sei registered (they may still be registered from before change of rules)

No6

Hi legs PM me the details or post a link on that please, I am currently looking at it for one client, i hadn't heard about it.

MicktheMan

Legs,
can you pm me too please. Thx

SilverBER

I attended an external insulation course in Limerick with some fellow tradesmen and, as a whole, we were left very underwhelmed by the whole experience. Its a 100mm board mechanically fixed to the wall and finished with a premixed Artex-like preparation. My first thought was how to fix a satellite dish, clothesline, downpipes, etc to the surface but the course facilitator couldnt provide any answers.
SEI use an Agremented SYSTEM and this is the one as described above but it is definitely not the answer. I wonder if there is a case for using a CE certified system in its place as a challenge to SEI under restrictive practices.

MicktheMan

Can you pm the system name/supplier.

Was 100mm board the max thickness or can you fix thicker (f.i. 200 or 250mm)?

Also, was any information given on the effectiveness of the insulation when applied to cavity walls where the cavity is either empty or partially filled?

d'Oracle

I thought I read in Construct Ireland that 2 suppliers have the Agrement cert?

legs_akimbo

d'Oracle wrote: »

I thought I read in Construct Ireland that 2 suppliers have the Agrement cert?

This is where i read it too, but can not lay my hands on last months issue to clarify what was written, sorry !!

johnnymorgan

I know this is an old thread..

I am looking at this idea myself(more spitballing now) but is somehting I am thinking about..

my house is 200m2 dormer bungalow so a good size to outside insulate. It has a red brick facade in parts and chips in other..

I have a ber of c2(198kw/h/m2/yr) so just about squeeze into the c2 bracket of 200..

1. How much would it improve my house to get this done
2. How much would cost be, I know there are grants of a few thousand that can be availed of as well..

any help appreciated,
J

BryanF

Why grave dig threads? 9years old? Why not just start a new one?

1. Lots
2. Lots.

What’s the external surface wall area? how much do you spend on heating? how quickly the house cools down? Have you read the thread?

Edit: costs around 120-150 p/m2 external surface area

johnnymorgan

BryanF wrote: »

Why grave dig threads? 9years old? Why not just start a new one?

1. Lots
2. Lots.

What’s the external surface wall area? how much do you spend on heating? how quickly the house cools down? Have you read the thread?

Edit: costs around 120-150 p/m2 external surface area

I didnt know was issue to post on old thread.
I read old thread through..

Im not sure how much external wall space I have. Have to try and determine..

I know its expensive so trying to see if worth it. It cools sown quick enough but to be be fair I dont leave on heating non stop as too costly to do that.

Do you know any companies hat can do ab assesment for free?

Rgds,
J

MicktheMan

johnnymorgan wrote: »

my house is 200m2 dormer bungalow
1. How much would it improve my house to get this done
2. How much would cost be, I know there are grants of a few thousand that can be availed of as well..

johnnymorgan wrote: »

It cools sown quick enough but to be be fair I dont leave on heating non stop as too costly to do that.

Do you know any companies hat can do ab assesment for free?

Before you do anything on insulation (external or otherwise), have the house tested for air tightness... and pay for it (free assessments are worth exactly what you pay for them).

On your 2 questions;
1. If (as I suspect) your house's predominant heat loss mechanism is air leakage then EWI will have minimal, if any, positive effect until the air leakage issues are addressed.
2. Just because there are grants for a particular measure does not mean it is an appropriate measure for your house.

johnnymorgan

MicktheMan wrote: »

Before you do anything on insulation (external or otherwise), have the house tested for air tightness... and pay for it (free assessments are worth exactly what you pay for them).

On your 2 questions;
1. If (as I suspect) your house's predominant heat loss mechanism is air leakage then EWI will have minimal, if any, positive effect until the air leakage issues are addressed.
2. Just because there are grants for a particular measure does not mean it is an appropriate measure for your house.

Thanks Mick for your comments. That's a good point of what you pay for. Im looking more at doing this in a year or more so trying to research some improvements in meantime. I need to improve ventilation in couple of rooms as well first(i.e there are no vents )

And would need to see where the air is escaping alright.

Food for thought.

Yes I understand on the grant. At least it is there if I do decide to take a measure(and it was appropriate).

Cheers,
J

BryanF

johnnymorgan wrote: »

Do you know any companies hat can do ab assesment for free?

Rgds,
J

:rolleyes: