Deleted 6 December 2022 at 12:09PM edited 12 January at 11:56PM in Green & ethical MoneySaving 35 replies 1.2K views

zeupater

Deleted_User said:

zeupater said:

Deleted_User said:

zeupater said:

ABrass said:

If you retrofit to Passivehaus standard your heating bill will be virtually zero. Solar gain and the heat of people in the house balance loss to the outside world.

Hi

Exactly ...... a good proportion of out heat load is delivered through solar gain, the high levels of insulation slow the heat loss process & the thermal mass acts to regulate temperature over time so that the time between periods of solar gain or other heat provision can vary considerably without too much impact ....

As mentioned a couple of days ago, we were expecting a few days of sun to arrive today, so didn't panic & run heat sources to compensate for the recent dull weather ... as expected it's arrived, so the heat pump is running at full tilt to help recharge the thermal mass ....

We're not passivhaus standard, but do meet some of the main energy criteria ...

HTH - Z

So you've gone down this route? How much did it cost you?

Also, what type of home do you have (detached, house, bungalow, semi etc) and what part of the country do you live in? So for example, big difference between South of England climate and Scotland.

Here's a rough spec outlying what you need to fork out for in order to achieve this virtually zero heating bill (theoretically). What is the break even point (especially if your heating is free due to abundant supply of firewood):

"

How to achieve the Passivhaus Standard in the UK

 To achieve the Passivhaus Standard in the UK typically involves:

• accurate design modelling using the Passive House Planning Package  (PHPP)

• very high levels of insulation
• extremely high performance windows with insulated frames
• airtight building fabric
• 'thermal bridge free' construction
• a mechanical ventilation system with highly efficient heat recovery"

Hi

Covered most of your points in various recent posts, but as mentioned, we don't comply with the strict requirements of passivhaus, but do meet some significant aspects regarding energy requirements, so it's effectively irrelevant, especially so as we're discussing the justification of energy efficiency improvements based on cost & return ...

As for location, well that's moot ... you may live north of many reading this thread, but as you've already mentioned, you're in a relatively mild area ... for example, if you're anywhere near South Ayrshire then the Met Office forecast here is probably similar or cooler here than there over the next week, and that applies to the rough correlation of temperatures we've both been mentioning so far, so it's not likely a significant consideration ...

Anyway, whatever we have improved was done well over a decade ago and you're the one asking for information whilst continually dismissing suggestions others may make ... many years ago someone gave me some advice I consider pretty pertinent and it goes something along the lines of  ... you have one mouth and two ears for a reason, could it be that it's generally considered to be twice as important to listen than it is to speak? ... 

HTH - Z

It's not an inquisition! LOL I'm not pressurising you for answers. But if you are wanting to give me the information that I've asked for - I'm just trying to give you feedback. You haven't answered the question I'm asking. It's cool if you don't want to.

To be clear for anyone reading. What I'm asking for is :

a) Costs involved in retrofitting a state of the art insulation (and details of what's involved) - or cost of the house if it was a newbuild.

and 

b) How long it takes for temperatures to drop when all heat sources are switched off - for example, during days of freezing temps with lows of -4 and highs of 3.

Hi

The costs today aren't the same as the costs a decade ago and your starting point isn't a new build. The question at hand is simply one of improving thermal efficiency of your property where you are ...

I, and probably others, could give you chapter & verse on our various improvements, some of us may even have cost justified all potential improvements, established a plan and then chosen which elements to implement, but that doesn't apply directly to you ...

It's the way you approach what you're trying to achieve that's important, unfortunately what is right for others may not be right for you & costs applicable to others may not be the costs applicable to you ...

For example, let's say you decide to go down the efficiency path & buy a GSHP for your property as it is (perhaps to replace oil heating)  - the unit will be sized and priced to cope with your current level of heatloss and you may justify the cost based on future energy savings, but have you planned correctly, or just unknowingly planned to waste money??

Okay, let's expand upon the above .... after justification & installation of the heatpump you decide that you could continue on the efficiency journey and improve the loft insulation ... great, more savings, but also more expenditure ...

So where is this all going? ... at the very start a significant mistake was made - the cost of installing the heatpump was justified against efficiency savings which would have been shown to not exist if there was an established plan to work to .... maybe a plan would have shown that investing in the insulation before the heat-pump would result in savings so significant that a heat-pump couldn't be justified at all, or maybe it would show that a reduced heat load would result in significant savings related to the size & scope of the installation (reduced output, heating circuits etc) or even a cheaper solution based on a different technology (ASHP, A2A, PV, TOU/battery, direct thermal etc ...) ... maybe this would result in what we all should really be be striving for when chasing efficiency ... efficient use of capital!

After all .... Failing to plan is planning to fail ...

HTH - Z

chris_n

You can work the differences in how much heat you will use to maintain your temperature against a modern house out from the U values I gave earlier. You can't actually work out what b) is unless you know how much heat is stored in the fabric of the building and its contents.

zeupater

No worries - you clearly don't want to answer my questions. It's cool. Maybe someone else will.

Cheers.

Hi

The answer is that only you can answer the question related to your own property .... again, you're not listening to what others are saying ... it's just like the inability/willingness to appreciate what others were saying about the difference between Power (W) & Energy (Wh) etc from around a month ago ... eventually it clicked, but it could have clicked earlier ...

To play your game according to your rules, let's say that our first tranche of loft insulation cost us £500 15 years ago and paid for itself in (say) ~4 years and the second tranche cost £450 the year after, the cost of which was recovered over 6 years, what have you really learned?

Without knowing the area insulated, the u-value of the insulation, target internal temperatures for the periods involved, the existence of any offers that were available at the time of purchase, the ambient temperatures for the years involved, the internal/external delta-T maintained during the heating season for each of those years, occupation & heat provision patterns for the household, the cost of fuel per kWh purchased over those years, the conversion efficiency of the heat source, whether the heat source was changed over the period, applicable inflation rates for both materials & income, relative costs of goods in different areas of the country, delivery costs  ... and many, many other variables ... how can this be applied with confidence to what you're looking at as an exercise which is relevant today? ... 

My answer is the answer which was applicable to my property at the time when the improvement was made and in the order that we chose to make improvements .... the answer to the question for your property depends on your own set of variables and how you choose to prioritise & order the steps you're looking to make .... there's no other answer that anyone can honestly give for such a general question related to payback/ROI unless it comprises a wide time range .... our own identified & costed improvements showed payback periods ranging from a couple of months to well over a century ... suffice to say, the ones measured in months, no matter how small or costly, were prioritised ...

HTH - Z 

zeupater

Deleted_User said:

Again, I know the answers in relation to my own property.

I have asked a specific question that as of yet no one has answered. That's cool - if someone has the info I'm looking for they'll share it. 

Clearly you want to turn this into a completely different discussion. One that I'm not interested in. But batter on - someone else might be interested. 

Hi

But again, you don't seem to know ... your basis for loft insulation not needing attention is that the house is warm despite only using a 3kW log burner .... your post

So there's no problem with insulation - a 3kw logburner is very cheaply and efficiently keeping the whole house warm in sub zero temps. But what I'm trying to establish is the extent to which this can be improved upon - which is why I'm interested in the experiences of others

.. however, when this was later placed into context by ABrass estimating heat provision ...

You used around 30-50kW of heat (depending on how hard your log burner is working). You're probably burning 37.5-90kWh of fuel. That's not terrible for some very cold weather but it isn't award winning.

Which you later attempted to lay to rest by suggesting a zero marginal cost of heating, which could possibly be used as an argument to counter any ROI on insulation ...

Here's a rough spec outlying what you need to fork out for in order to achieve this virtually zero heating bill (theoretically). What is the break even point (especially if your heating is free due to abundant supply of firewood):

However, a zero marginal cost for logs is inconsistent with your post I remembered from 6th November, which suggests an average marginal cost far above £zero ... link  ...

We have a 3kw woodburner installed in a 20 year old bungalow with good insulation. We did the installation ourselves - saving a lot of money. 

We managed to get hold of about 2 cubic meters of greenwood for free which we're seasoning ourselves.

We purchased 8 cubic meters (loose) of seasoned wood from Whitehorse Energy when it cost £100 per cubic meters (it's now £200 per cubic meter)

We purchased 4 cubic meters from a local supplier for £90 per cubic meter.

We have a big woodstore obviously!!

Based upon what we used last winter I think we'll get through the winter on about 3 cubic meters. That's using the fire all day some days, and lighting it at 5pm others. Depending upon what we're doing that day and how cold it is.

... but more likely 11p/kWh.t based on a replacement cost of £200/cubic metre tipped if your burner is operated efficiently ... unless you have a reliable source of free firewood to call upon as required, it's this replacement cost of somewhere around 11p/kWh.t that should be considered as the marginal cost of operation for the log burner to offset against the cost of insulation ... 

You need to do your own research based on your own skill sets ... if you managed to install a log burner yourselves (which some would consider, let's say, odd) then you probably could go down the DIY loft insulation route, so what you need to know could simply boil down to the calculating differential of the heat-loss between the current u-value and whatever the new u-value would be, then applying a value to the kWh.t savings (possibly the 11p) to see if the investment in rolls of insulation makes sense .... it's pretty simple really and would apply to your property as opposed to someone else's, after all, your stated goal for this exercise was basically summed up as ...

This isn't just idle curiosity. You need to know what performance is at the top of the range. Then consider how big the gap is between what you have and that high end system. If the difference is absolutely huge, then there's scope to save money long term by investing in more insulation. But I suspect that once you've got a basically warm house (which I have) there probably aren't going to be any cost effective improvement that you can make.   

... where you seem to both concede that you'll need to measure current performance in order to understand the gap and therefore cost the investment ... and ... immediately go on to discount the need for such an exercise through applying assumptions based on nothing other than feelings, which suggests to anyone applying a logical approach that "Again, I know the answers in relation to my own property" may not be consistent with an approach to gain the answers you're searching for ...

HTH - Z

silverwhistle

Deleted_User said:

I have asked a specific question that as of yet no one has answered. That's cool - if someone has the info I'm looking for they'll share it. 

Clearly you want to turn this into a completely different discussion. One that I'm not interested in. But batter on - someone else might be interested. 

They probably won't answer since you don't seem to listen to useful information. Sometimes you need to do your own synthesis from the information that people _DO_ provide. But it is a remarkably obtuse attitude if you come to a forum asking detailed questions from others to meet your own exact circumstances.

Zeupater has shown a great deal of patience and provided some very useful information. I've a mid-terrace in Hampshire with a wood burner and I'm not going to suggest anything as nothing I say will meet your pugnacious requirements for a matching experience.

zeupater

Deleted_User said:

silverwhistle said:

Deleted_User said:

I have asked a specific question that as of yet no one has answered. That's cool - if someone has the info I'm looking for they'll share it. 

Clearly you want to turn this into a completely different discussion. One that I'm not interested in. But batter on - someone else might be interested. 

They probably won't answer since you don't seem to listen to useful information. Sometimes you need to do your own synthesis from the information that people _DO_ provide. But it is a remarkably obtuse attitude if you come to a forum asking detailed questions from others to meet your own exact circumstances.

Zeupater has shown a great deal of patience and provided some very useful information. I've a mid-terrace in Hampshire with a wood burner and I'm not going to suggest anything as nothing I say will meet your pugnacious requirements for a matching experience.

All over these boards people post about what the temp was last night and what it was when they got up. It's a very simple question and I have a very specific reason for wanting an answer to that question for someone that has state of the art insulation in their home.

No one is under any obligation to answer, but this thread is asking for that information OF ANYONE WiLLING TO GIVE IT. If someone wants to provide screeds of useful info about something else they could start another topic. I might then join in. 

I am not asking for information about my situation. I reiterate - yet again:

To anyone that has invested in state of the art insulation (or has a new build with this installed)

1. How much did you spend on your state of the art insulation (so presumably ultra high efficiency windows, insulation, mechanical ventilation etc)?

2. How rapidly do temperatures drop in your house when all sources of heating are turned off.

Hi

Again, and listen/read very carefully before (hopefully) understanding ....

The answer to 1 is irrelevant because every property is initially different in type, location, aspect, size, age, base insulation levels etc .... silverwhistle lives in a mid terrace house and will therefore, assuming the neighbouring properties are also heated, benefit from a significant reduction in heatloss ... ours is detached, set in >1/2 acre main garden with open aspect fields at the back & woodland about 50 metres to the front ... the nearest property we can see from the upstairs windows is well over 100m away, therefore we're not likely to benefit from anyone else's heating ... the house is a one off architect design, somewhere around 3-4x the size of an average UK property and was built with a number of specific efficiency measures & materials which aren't even general planning requirements today ... hopefully you can see that any efficiency improvement measures applied to the two properties would have both a different starting point, may have different priorities, and therefore likely a considerable difference in cost too ....

Now, an attempt to address 2 (yet again!) ...

We display/measure temperatures in 9 fixed internal locations as well as outdoor ambient via a weatherstation .... the temperature for each location is different but the average overnight drop is probably well within 0.5C-1C at this time of year before recovering most of that through solar gain (if any!) the next day, however, some of the temperatures actually rise overnight, even with no overnight heat provision .... see the problem yet ?? ...

The issue, as explained multiple times, is that apart from raising the temperature in our main sitting area with a small heat-pump (for comfort), we're currently using no other energy for heating  ... yes that's right .. NO ENERGY FOR HEATING ... solar gain, 6kWh/day of imported electricity, whatever we generate & use from our PV, around 35kWh.t of gas to top up the DHW  since last March ... oh, and about 8hours of running the log burner after sweeping the chimney in early November is all we've used .... now think this through ... if we're not using considerable energy for heating and we haven't frozen solid yet, how much do you think the average temperature drops for us are ....

So what have you gleaned from this trove of information which is useful .... absolutely nothing ... why? .... because it's irrelevant when applied to your own property for comparison as per your stated intent ...

But what I'm trying to establish is the extent to which this can be improved upon - which is why I'm interested in the experiences of others

... so what were the costs for us? .... inconsiderable compared to the benefit we've received and the value of the property, but then again it's related to a unique property which had a considerable efficiency advantage over most from the start (eg in-floor insulation), but then again, what should be included if a sum was established ... the log burner, solar PV, solar thermal, loft insulation, loft insulation again, insulated doors & hatches, draughtproofing, heat-pump, high efficiency boiler, automation, independent thermostatic controls, the trombe wall solar porch .... and on, and on .... effectively you try to improve all the time and don't waste resources in the process ... so where's the cut-off between 'investment' & 'comfort', especially when everyone's perception, resources & needs are different? ... as said, any form of comparison which can be derived from valuing our specific costs will be irrelevant, over that, how would you rebase various costs incurred over varying periods to perform such a comparison .... we started ~30 years ago & haven't finished yet!

HTH - Z          

paul991

I live on a estate of 400 houses of ten different designs i would love to know how similar houses have been improved insulation ect
ect .I have done all the basic things loft cavity insulation draught excluders windows ect . I don't understand why some people think its a strange question to ask and to get the answer in a non over technical term.

ABrass

paul991 said:

I live on a estate of 400 houses of ten different designs i would love to know how similar houses have been improved insulation ect
ect .I have done all the basic things loft cavity insulation draught excluders windows ect . I don't understand why some people think its a strange question to ask and to get the answer in a non over technical term.

Because without the specifics of what is in place there is no way to discuss what you could do.

And because when people have offered information about what they have done it has been dismissed as not relevant because of location or type of building.

There's nothing wrong with the intent or goals, just bad forum manners.

paul991

Its the way people have turned on the question .I am lucky  i can talk people with the same building and ask what they have done and to  what effect it has on their bills as they have a similar building in the same location . Scarter gave  some idea of his property and  any one in a similar property could of given basic advice.If more technical modeling is required there are free courses on the open university website. 

born_again

paul991 said:

I live on a estate of 400 houses of ten different designs i would love to know how similar houses have been improved insulation ect
ect .I have done all the basic things loft cavity insulation draught excluders windows ect . I don't understand why some people think its a strange question to ask and to get the answer in a non over technical term.

Best way. Go knock on some doors & ask. 
Look at your question. How much detail is there about your house? Age, rooms etc Info given = useful return of advice 👍


It's the same as the Op question.
Finding someone with a 4 bed bungalow in the same area (or situation) that is a new build, with state of the art insulation. Slim to none at a guess.

But there have been some fantastically informative posts in this thread.