Insulate the Attic

Introduction:

 

 In summer 2022 energy prices were shooting up. Various websites highlight this as one of the fastest payback and high impact jobs to improve house insulation (eg  https://energysavingtrust.org.uk/advice/roof-and-loft-insulation/) ...

...my only worries were our existing floorboards and attic junk making this a big job. I also worried about the likelihood that everyone else had the same idea and there would be a global shortage of insulating materials.

 

What we had before:

• Approx 100mm of insulation, made up of:
• Central portion of attic (below floor boards) - Kingspan (this has approximately 2x the insulation properties of regular fibre insulation, given the same thickness)
• Approx 100mm of very old fibre type insulation

 

What I added:

• Insulation: "itch free" (https://naturalinsulations.co.uk/product/supasoft-insulation/ ). This was placed on top of the existing insulation to get approx 300mm across the whole attic.
• Loft Stilts (https://www.loftstilts.co.uk/). It is only afterwards that I have realised that there are multiple brands (eg Loft Legs) doing a similar job; I did not do any comparisons before purchase.
• I also needed some screws for the loft stilts, but everything else was existing (floor boards in central portion of attic, large access hatch, lighting, etc)
• Costs:
• Insulation: £1,015 (including shipping)
• Loft Stilts:     £145
• Total:         £1,160

 

The Plan:

• Clear out junk from the attic (hired a small skip)
• Move remaining stored stuff to one end of the attic
• Lift floor boards at the other end
• Add loft legs
• Add insulation - now around 300mm across the attic
• Replace floor boards

One end of the attic complete (you can see attic junk at the edge of the picture)

 

• Move 50% of stuff from one end to the other
• Lift floor boards in the centre, etc
• Move 100% of the stuff to the completed end
• Repeat process on final end
• Re-distribute stored stuff

 

Execution:

• Looking online it seems to be simply a matter or rolling out the insulation. It is all the other things that take the effort and a bigger job than I had at first envisaged
• It was hot and sticky work (Sept/Oct):
• How long did it take? - hard to judge as I did the work at weekends over a few weeks and did not work every day. The work took about 10days, working 4 or 5 hours each day (working longer in the cramped conditions was too much for me).

 

Lessons Learned:

• I wish that I had thrown away more junk - there were some long floor boards, so you needed space beyond the area being insulated.
• Our attic has reasonable lighting in the centre (two strip lights), but still not good enough. In hindsight installing lighting throughout, before I started would have made it easier (& easy with some LED lamps).
• I was worried that loft legs did not look robust enough. I needn't have worried the floor boards structure, with loft legs underneath is rigid and feels robust.

Cross-section view at attic hatch with one loft leg visible - the overall structure feels rigid and robust

 

• There are quite a few useful 'how to' guides on line.
• Using non-itchy insulation was a good move (the limited amount of original fibre glass insulation was bad enough)
• Not doing this at the height of summer was a good move
• We have a relatively large attic hatch with a built in ladder - if you do not already have this, then worth installing ahead of insulating, particularly if you use the attic for storage.
• I needn't have worried about a global shortage of insulating materials - the suppliers website promised 3 days and the insulation arrived in 3 days.

Insulation arrived within 3-days. Despite rapidly rising energy prices, there seemed to be no shortage on insulating material

 

Impact:

• Combined with other changes (small reduction in room target temperatures (1degC in some rooms) and reduced boiler flow temperature from 70degC to 65degC) this looks to be saving ~£300/year (see upcoming blog post with September '23 data) It is difficult to be certain which of these is the biggest impact; my expectation is that the majority of this is the loft insulation:
• We have since restored some of the temperature settings and it has not made that much difference to costs)
• My understanding is that the flow temperature has to be lower than 65degC to make a significant improvement in boiler efficiency (more on that in a future blog post on weather compensation)
• Increased comfort: The house felt warmer (eg in the morning when the heating had been off all night) & also warmed up quicker.
• I think that we can run with heating off completely for longer over the summer/autumn.

 

My summary:

While it was more effort than I had envisaged, definitely worth doing and a good return on investment at perhaps 4 or 5 years.

 

Smart Heating Controls - My Experience with Honeywell Evohome - Part 1

Introduction

During lockdown in 2020 it seemed like a good idea to get better control of our heating. My focus was better comfort, but saving energy would also be good. We had Evohome installed in September 2020.

 

So, with the perspective of 3.5 years after installation (Jan 2024), how has the system performed?

 

Note: when I wrote this review it grew and grew...

...I have therefore split it into two: in this post I have attempted a less technical overview and in an upcoming Part 2 I will focus on technical points.

 

What Did Evohome Replace and What Were the Problems

We had a simple dial thermostat in the hall; a 7-day programmable timer in the kitchen with traditional (1-5) Thermostatic Radiator Valves (TRVs) on each radiator:

• The 7-day programmer was a bit of an effort to set up. It was set to go on in the morning and evening during the week and all day at weekends. We hardly ever adjusted this over many years, other than on initial set up.
• We controlled temperature day to day by:
• Adjusting room thermostats (often to maximum or minimum)
• Adjusting the hall thermostat (often by quite big increments to get the 'click' of the contacts to 'kick' the boiler on or off)
• 'Advance' on the timer, eg in the evening, if we were staying up past the time when the timer went off.
• The bathroom was set to be always on (ie if there was hot water flowing to the radiators then the bathroom radiator was on) - it was explained to us by the installer that this was necessary as a pressure release if all the TRVs are off and the boiler is on.

All of this resulted in quite wide swings in temperature, a few household arguments and a few times waking up with a hangover, dehydrated and a really hot house because the heating had been on all night with radiators at maximum, after a late night drinking!

 

Selection & Installation

At the time I read various positive reviews of the Evohome system and it looked to be the only system to give individual radiator control.

 

The Evohome website gave me a local installer who quoted me based on photos of the existing TRVs, so that he could confirm there were no issues in the retrofit:

• 11 rooms/radiators to be fitted with a smart TRV
• 1 x hot water tank thermostat
• The price, with installation, was ~£1800. This included for an Automatic Bypass Valve (ABV) to allow all radiators (including the bathroom) to have Evohome TRVs (see part 2 for more details).

 

Installation was mostly straight forward and took one day; however there were a few gremlins. See part 2 for more details, but these would have been fixed in a couple of weeks / 2 visits by the installer, except that we had a pre-existing wiring fault, that credit to the installer, he tracked down and fixed (at additional cost).

 

By the end of October installation was complete, the system was now working well but our confidence in the Evohome system was low  (especially for my wife who just wanted a working system!) We had seen repeated gremlins and, even excluding the wiring fault, I had to resolve several issues during the first couple of months. Limited online support materials meant that this was somewhat trial and error (ie there may have been very few issues, but perhaps I initially caused more as I learnt how to trouble shoot).

 

Lessons learned:

• Ask the installer how many systems they have installed and if your installation has anything that they have not tackled before or that they see as a problem.
• Get a fixed price and defined scope of work (eg what happens if there are problems). Agree upfront the hourly rate for fixing problems that are outside of this scope. I had done this & so the agreement on extra costs (ie wiring fault) was transparent and there was no argument.
• If there are tricky issues then you need an installer who will stick with it and not give up. I got that in this case, but I am not sure how to judge this other than a sense of if you trust the installer. I think that to my benefit this was a smallish local company and I always got Mike to come and look at problems. I can imagine that  with some (larger) companies you might end up being passed around from person to person.
• I strongly recommend that anyone having Evohome installed takes an interest in the technology and any issues - I ended up learning more about central heating and Evohome than I really wanted to, but this ended up being useful longer term (see below and  part 2). It also gives a lot of materials for a very long blog post!
• Plan on an early summer install. Why? You will have plenty of time to learn the system and resolve issues before you really need Evohome to be 100% functional in winter. In addition, your installer/heating engineer will have better availability and may have lower hourly rates. My September install got into reliable operation just in time for the onset of winter proper (end of Oct), but I had to pay winter rates for some of the additional work.
• After the initial gremlins the system settled down and our confidence grew.
• Evohome has been working pretty smoothly for over 3 years now. Part of this is because when we do get issues (every few months) I have learnt enough to resolve them myself. This is much like other home technology that we have (eg phone, laptop, printer, etc) other than there is less material on YouTube to help.

 

Evohome Software

The software is pretty easy to use:

• Programming a new schedule is reasonably simple. It is much easier than our old 7 day controller.
• There is space for 1 extra schedule.
• The radiator temperature control is intuitive; it overrides the scheduled target temperature and then at the next scheduled temperature change the radiator controller returns to the scheduled target temperature.
• The handset and phone apps have different interfaces. Neither is better or worse just different.

Hand controller scheduling interface	Hand controller temperature override interface
iPhone scheduling interface	iPhone temperature override interface

• There are controls for the entire system (eg for when you go away), but these are limited:
• App 'Eco' mode on: with scheduled switch off time resolution of 1hour - reduces room temp by 3 degrees (but seems to have a bottom limit of about 16degC)
• App Heating On / off: switch on time has one day resolution & this does not turn off the hot water.
• Hot water has to be switched off/on separately from the heating
• The handheld display is different, but not any better.

 

The Evohome software is easy to use and fine for day to day operation - if you are considering buying Evohome do not get put off by the details and recommendations for Honeywell in part 2.

 

Living with Evohome - How we use it:

• We are getting used to switching the heating off when out:
• If we are out of the house for a few hours we tend to use Eco mode as you can set the on time by the hour
• For longer than one day we switch the heating off and try to remember to switch it back on from the phone app several hours before we are home to allow for warm up time. We also have to remember to switch the hot water off/on.
• We have the schedule set to turn off several times in the evening/night, eg 10pm, 11pm and midnight. This allows for those late nights:
• At 10pm the heating goes off (target 5degC)
• If we are staying up we can turn up specific radiators (usually at the radiator)
• These go off again at 11pm...etc.
• This prevents the heating being left on all night, in every room and waking up dehydrated (as well as hung over) as with our pre-Evohome heating control system.
• We have the schedule set to nudge up the temperature in some rooms in the evening; not sure if this is the same for everyone, but 19degC/20degC seems fine in the daytime but cold in the evening.
• We keep lounge cool and use a nice and cosy gas fire. The gas fire is not the most efficient, but has a really nice log effect. My suspicion is that this saves energy (cool lounge for much of the day and in late spring/summer/early autumn we often just use the gas fire and extend the time when the central heating is off completely).
• Battery costs:
• Each TRV (& the hot water thermostat) take 2 x AA batteries
• Very roughly each battery pair lasts 18months
• On our system this is about 24 batteries every 18months or 16 per year
• Amazon price £8-99 for 40 pack of batteries, or around £3.60 per year.
• Central heating service - no change, we still use the same bloke to service the boiler (ie not the Evohome installer) and I do the Evohome (battery replacement + occasional trouble shooting)
• The radiator controller does make a whirring noise when it adjusts the valve. For me this has become a re-assuring 'all is OK' sound. In most rooms the sound level is similar to the boiler firing up (ie not very much). However, it is another reason for not having 'optimum start' configured - at 6am every morning the radiator TRV in our bedroom makes its small whirring sound and the boiler fires up a few seconds later. Often I sleep right through this, but sometimes I am stirring early and I know what time it is; I am not sure that I want this noise varying between, say, 5am and 7am depending on how cold the morning is (but I may still try it).

 

My view of Evohome after 3 Years

• Comfort:
• Consistent and controlled: improved comfort through the day
• Heating not left on all night; waking up dehydrated and hot never happens now.
• To start with my wife hated the faff of learning a new system and teething issues with Evohome (over the 1st couple of months), but after 3 years she now prefers Evohome to our older controller.
• Ease of Use:
• Straight forward. Most day to day operations are:
• Adjust a room thermostat (easy on the app if we are out, but even easier to just change it at the TRV)
  

Adjustment of room temperature using the TRV knob is easy and the temperature automatically returns to schedule at the next scheduled time point.

 

• Turn heating off when we go out and back on before we come home (or using Eco mode to turn it down and then back up)

• Reliability:
• No hardware failures in 3+ years
• After initial 2 months/teething problems, perhaps one fault very 3 or 4 months (mostly resetting a TRV, and one receiver reset) + battery replacement.
• Batteries last 18 months, but each TRV and the hot water thermostat has them, so with 12 sets of batteries I end up changing one set every month or two. The TRV error message for batteries going is clear; it comes up on the handset and gives good early warning. The hot water thermostat battery warning was obscure ("comms fault") and I only discovered that changing the batteries fixed it by trial and error.
• Note battery life on the hand held display is poor. You can take the handset out of its nest for a few minutes (ie the opposite of a mobile phone that needs occasional charging, but spends most time away from the charger).

 

Financial Payback:

Evohome probably saves us some money each year, but the data on money saving, in our house, is mixed up with lifestyle changes (See earlier blog post, eg working at home in the pandemic) and also mixed up with other energy saving measures (eg loft insulation - see future blog post). So the impact of Evohome is hard to measure on its own. I read of 10% savings quoted by others and I can believe that this is true. That would be ~£200/year for us at current energy prices, so a payback of a little under 10 years plus a more comfortable house. I also think that Evohome gives you more control on saving money Vs comfort, ie you have the control to fine tune the savings to be more than the quoted 10%, if you are OK with lower temperatures (in particular rooms/times).

 

Final Thoughts:

• Evohome works well and, for us, is working as promised. My sense is that a complete technophobe might struggle, not in day to day operation, but with the faults that do occur every few months. Reading recent reviews (eg https://www.techradar.com/reviews/honeywell-evohome) it sounds like Evohome is still one of the leading systems and also one of the most user-friendly. If that is the case (& if my system is typical) then my view would be that smart radiator controls are not ready for the mainstream quite yet:
• Better support materials required (3rd party and supplier)
• Better guided fault diagnosis and resolution within the system (eg my 5 year old, low cost, HP printer is great for this)
• Build in more fault tolerance (see part 2 for more on this)
• The length of this article tells you that, from knowing very little about central heating, installing Evohome has taught me more than I ever wanted to know.
• If you are moderately technology savvy (eg comfortable trouble shooting home wifi, printers, laptops, etc) and interested to learn, then you should be fine (I have an Engineering background, but I am sure that this is not necessary). However, if your first response to any technology error is to call someone else then you should anticipate a cold radiator or two, once or twice each winter while you wait for help to arrive! When help does arrive, if this person is technology savvy, but new to Evohome, then the lack of online support materials will be a hindrance.
• Evohome has given us a more comfortable home; we get a more controllable & consistent temperature. My wife was dubious early on, but now likes Evohome purely from a comfort/control viewpoint.

 

Introduction

Home Energy: Is 'Going Green' a Good Investment & Worth the Effort?

 

We have lived in an English 1970's 4 bed detached house for over 25 years. We have made a few improvements to energy efficiency, but more with a view to making the house more comfortable to live in...

...roll on 2021 and 2022 and energy prices take off. It seemed like a good time to take stock:

 

Which investments are worthwhile and which ones are not worth doing?

 

This question actually turned out to be much harder to answer than I had expected - various websites had useful indicators but mostly lacking hard data that I could apply. Hence this blog where I plan to show the impact of various 'green'/money saving measures in a real house lived in by real people.

 

Here was my 'audit' as of Autumn 2021. We have:

• uPVC double glazing
• Cavity wall insulation
• About 100mm of insulation in the attic
• Condensing system boiler (ie with hot water tank) running at about 75degC flow temperature (more on flow temperature in a future post - in 2021 I didn't know what flow temperature was!)
• Smart temperature controls fitted (more in a future post)
• Most occupied rooms set at 20degC during the day and off at night
• Log effect open gas fire (it looks nice, but is not the most efficient)
• LED bulbs through the house

 

What we could do:

• More insulation in the attic (eg 300mm seems the norm now)
• Insulate central heating pipes in the garage
• Heat pump to replace boiler
• Reduce flow temperature to 65degC
• Reduce central heating set point to 19degC
• Add solar panels

 

There are various websites that help you work out the return on investment:

 

https://energysavingtrust.org.uk/energy-at-home/reducing-home-heat-loss/

https://www.snugg.com/

 

 

but it seems too many variables to really get a good grasp of the return that you might get in real life (eg no one covered my uninsulated pipes in the garage - perhaps just too obvious!). One aspect that I could not find good coverage for is the effect of life style patterns. As of 2021 my wife was retired and I was working in an office. How would this change when I retired?

 

I did my best to gather up some historic data on our energy usage:

 

 Fig 1.1: Energy usage over subsequent 12 months and key events

Graph Notes:

• Each column shows the cost 12 months energy usage normalised to  Aug 2023 rates (including standing charge)
• Data capture was inconsistent - rarely an exact 12 month period - here I have normalised to 365days (this will introduce a small error depending on if the discrepancy/adjustment is summer or winter - worst case was 26days)
• The 2009 bar is a 7 year average to 2016; otherwise I have made no attempt to average out 1off factors like weather or a winter holiday.
• House size: 186m2, on two floors with integral single garage (see https://calculator.bcis.co.uk/measuring_your_house/measuring.aspx on how this was calculated)

What does the history tell us?

• Not much change in  the  period  2010 to 2017 (last remaining child still at home)
• 2017 to 2019 empty nesters, both out at work ~5days per week.
• Condensing boiler looks to make ~15% drop in energy use (but the installation also added to the uninsulated hot water pipes in the garage)
• While there was a slight nudge up in usage when my wife retired, it really went up when I was working at home in the pandemic!
• Smart heating controls made no obvious immediate impact (they did make the house more comfortable and perhaps enabled later savings - see future post)
• My return to the office and insulating the central heating pipes in the garage look to have had an impact

 

The obvious things to try:

• Reducing flow temperature to 65degC - just turn the knob on the boiler (see future 'Weather Compensation post I have planned)
• Turning the room temperature down by 1degC - let's give it a go and see how we get on; will it be too cold?
• Insulating the attic sounds like a good ROI (eg https://energysavingtrust.org.uk/advice/roof-and-loft-insulation/ shows £1200 cost  & £475/year saving, but that is going from 0mm to 270mm, we already have an average of about 100mm).  There are also lots of pictures of it being just 'rolled out' - reality is different (see planned future post on insulating our attic - real life!)

 

Watch this space - I plan to write future entries on real life installation and the effect on a real house with real people living in it. Eg, what will happen with my retirement? (other than I have time to write a blog on heating a house)

 

My hope is that this adds to the somewhat abstract information that is widely available online.