This is Part 2 in our battle with cold in our lounge. You can read Part 1 here Draught Problems: The Battle With The French Doors. We ended Part 1 waiting for the air distribution boxes for our MVHR to be insulated, the window company to replace the side light in our lounge French doors and the builders to seal under the external doors. We had been thinking that we were starting to gain the upper hand in our fight (scoring the battle as Residents 6 French Doors 6). How foolish we were!
Phase 13: MVHR System Air Distribution Boxes Insulated
The good news is that the air distribution boxes now have 100mm of Celotex surrounding them, combined with mineral wool so it’s goodbye to chilly air from the MVHR vents.
Well almost – when the work was going on in the very tight space that is our loft it was discovered that one of the bedroom ceilings had not been insulated at all. Not only that but it appeared impossible to get access to lay mineral wool to insulate the ceiling and the ducting running to the vent there. That explains why my office (AKA bedroom 3) is so chilly.
The builder decided that probably using a pumped cellulose insulation was the easiest way round it as the access was so difficult. We will call this phase a draw. Some progress on one aspect but we will have to wait longer until the bedroom is insulated.
Residents 7 French Doors 7
Phase 14: Sealing Under The Door Sills
We were expecting the next action to be the window company replacing the side light to the French doors. However they cancelled the appointment as the side panel had not been produced in time.
As we were freezing and wanted something done we asked the builder to at least seal under the door sills of the other three external doors. They obliged by sending two guys to lift the patio slabs to allow access under the door sills.
The photo to the right shows the unsealed sill of one of the external doors.
You can just about make up the DPC under the sill (click on the image to enlarge it). It’s the wavy grey shape under the sill. Once I took the photo the underside of the door sill was siliconed to seal the gap and the patio slabs replaced.
It seemed to make a small difference but it was hard to tell. We were a bit surprised and somewhat disappointed it didn’t make more of a difference. Maybe taking out and re-installing the lounge French doors would give us a better understanding of the issue. At least it was a little progress.
Residents 8 French Doors 7
Phase 15: Replacing The Side Light And Re-Installing The French Doors
The great day came at last, about a week later than originally promised. The window man came to remove the French doors, replace the side light and the re-install. I was there to document the event; the pictures tell the story better than I can.
Once the French doors were re-installed we left it until the next day to cut back the expanding foam and then the brickwork/frame was sealed with grey silicone. We no longer have a cracked sidelight and under the door sill is sealed with expanding foam and then silicone. We were thinking we should be nice and warm now. Victory was finally ours.
Residents 9 French Doors 7
Phase 16: It’s Still Cold In The Lounge
We are still cold. It’s beginning to dawn on us. The fight is not over. The battle we have had over the last few months to fix the MVHR system and the lack of seals under the door sills has maybe improved comfort in the lounge by 25% but it’s only gone from unbearable to discomfort. The rugs come out over the knees again and we pause for reflection.
The French doors seem as good as they are ever going to get. The room feels a different sort of cold now; not the damp draughty cold but like a cold fog. Maybe we are going mad? Maybe our bodies have altered and they just can’t respond to temperature properly? To check our sanity we take further images of the lounge walls around the French doors.
Despite re-installing the door frame we still have low wall surface temperatures: 8.4°C at the top corner of the door recess and 12°C a bit further away. Even the main wall is looking a bit cool at 14.3°C. Before you ask, these images were taken with the heating system on.
In the corner of the room next to the French doors the wall surface temperatures are decidedly on the cool side. In the picture above the spot temperatures points Sp1 and Sp5 are a bit hidden (behind the temperature scale and the actual temperature readings). Even 1 metre away from the French doors, at point Sp4, the surface is only 13.8°C. There does not seem to be a draught here; just cold walls. The sockets don’t seem to be letting in any cold air. So what can it be?
Our thoughts turn to the drylining of the walls and another theory emerges. What if air is getting round the doors and windows in some way and then getting behind the plasterboard so we are effectively sitting in a plasterboard tent surrounded by cold air? The plasterboard walls are a sort of dot and dab affair. How continuous the dot’s and dabs are is impossible to assess without doing some damage to the plasterboard on the walls. This could be one explanation of why some of the walls and floors feel cold even though the doors are now sealed properly. We reflect on this and realise we are now totally out of our depth as homeowners. There are no visible defects that you can look at and ask the builder to fix. Just a cold house with cold walls and cold floors and big energy bills. Depressing isn’t the word.
Phase 17: Winning The Battle But Not The War
The battle of the French doors is over. The battle of the cold house is yet to begin. We tell ourselves that sorting the MVHR system and the French doors are achievements in themselves but we are demoralised by the realisation that we still have the discomfort and we need to start to tackle things all over again. We don’t want this fight. We bought an energy efficient house so we would be snug and warm whilst we got on with our lives. Now we seem to be be spending a big slug of our time either trying to sort the problem or thinking about trying to sort the problem. For a moment we toy with just selling our new home but then realise it would be difficult to sell in its current state. We ask ourselves who would be stupid enough to buy a home that is supposed to be energy efficient but isn’t in reality? We look at ourselves; that’s just what we have done. We are the mugs who have bought a cold house that should be warm. We agree that we will have to take the pain and sort this; without it taking over our lives and creating more stress than necessary.
Residents 0 Unknown Foe 1
Phase 18: Maybe The EPC Can Help?
Whatever our real enemy is we have yet to see it; we can only detect it using thermal images and measuring energy bills. We need to motivate ourselves to take on this new foe. We know we desperately need reinforcements. Our thinking is that if the enemy can be detected in energy bills and carbon emissions then the EPC (Energy Performance Certificate) can maybe shed some light. That was what we used to help us buy the house; our EPC re-assured us the house was energy efficient and by implication warmer than the average house.
Fortunately, as I mentioned in Part 1, each EPC is a publicly available document on the web with an email address to contact the assesor. I send a follow up email to the assessor explaining our predicament and commenting that whilst he may have believed that we had an A rated energy efficient house built to level 5 of the Code For Sustainable Homes, the reality was somewhat different.
I wasn’t expecting much to come of this so I wasn’t disappointed when it didn’t help. I had recently heard Rod Burn from BSRIA declare at a Zero Carbon Homes seminar that an EPC was not worth the ink it was printed with. Someone else had explained to me that it was mainly a scheme to employ people, thus reducing the English unemployment rate!
The house, like all new houses, had been assessed under SAP. The EPC is a theoretical computer calculation based on the building design. Essentially throw some insulation and an air tightness test result into the computer and it tells you what sort of house you could have with those materials. Of course if the building isn’t actually built like that it’s not the fault of the computer or the person feeding in the data. I pointed out to the assessor that the energy consumption and carbon emissions were well out of line with the EPC and over 400% of what was printed on the EPC.
I got a speedy and clear response from the assessor: “The figures you are quoting are estimates and are based on a notional building with notional occupancy levels based on SAP. These may not reflect how you are using the house and as such would not reflect the ‘actual’ energy consumption. These levels are also based on your homes regulated emissions. These do not include cooking & appliances.“.
I didn’t bother pointing out that we don’t use gas for anything else as we don’t have a gas cooker or hob. We even have solar thermal water heating so the water heating needed from the gas boiler is probably around half of that for the average house. Also the notional occupancy used in the SAP is a theoretical 2.757 occupants rather than the actual 2 who live there. I concluded that Rod Burn was right and that the EPC was not worth the ink it was printed with.
The assessor, under the current building process, did not consider it right to recalculate the EPC, even though they knew the carbon emissions were 300% out for our house. They worked using the data supplied by their client – the housebuilder. If the data was not right in reality then that was a problem for local building control and the builder not the EPC assessor. The assessor was polite and professional. It crossed my mind that the assessor’s response was very prompt so maybe they had answered this type of question a few times before but all credit to them for being efficient at their job.
So do beware. A new build EPC just tells you that there is a chance you might be warm and your bills low in your new house but there is no guarantee from the EPC assessor whatsoever that this will be the case. It is a tick box exercise to check compliance with building regulations. Nothing more. It’s hard not to feel it’s just a marketing con used on mugs like us by the housebuilding industry.
Residents 0 Unknown Foe 2
Phase 19: Over To The NHBC?
We decide to go back to the builder and tell them again about the continuing cold problems, share the thermal images and photos of the door recess and ask for their help. The builder says they are all out of ideas and there’s not much point in more dialogue on our data as they don’t have the skills to interpret it. It is suggested that it is probably better to get NHBC involved at this stage as an independent party who offer a guarantee on the house. I am somewhat surprised that the housebuilder feels they don’t have the skills to tackle the performance gap in energy use; partly because I have seen a photo and article in the local paper showing a sister company in the same group talking about their experience with energy efficient buildings and PassivHaus at a site about 40 minutes drive from our home. Surely they have someone who would understand? Still, what I want is a warm home that is comfortable to sit in so am willing to go down the suggested NHBC route.
Just for completeness we now have gas consumption data for February 2016 so I have updated out usage. We had a very mild winter and gas consumption for the 12-month period is now 7,673 kWh including water heating or an estimated 6,546 kWh for space heating alone. Space heating gas demand equates to 65 kWh per m² per year. During February 2016 we averaged 43.8 kWh per day of gas usage for space and water heating.
I show the data to my wife and tell her it looks like we have a house no better than the draughty old 1930’s house we had before, which had no cavity wall insulation at all. She tells me that our new house is actually much worse than our old home. In our old house the radiators and boiler were huge, so the space heating system could get the rooms up to temperature quite quickly in cold weather. It was comfortable but expensive to heat. The radiators and boiler in our new house are sized assuming the EPC is correct and that the space heating demand per room is small. Since the theoretical EPC vastly underestimates the actual space heating needs, the radiators are under size and in the wrong place. In our new home, once it gets cold, it takes a longer time for the undersized radiators to get it warm. It’s not as comfortable. She has a point.
So now we are up-to-date on the 2 March 2016. We await contact from the builder and NHBC to progress things further. A contact of mine predicts that NHBC will be next to useless when it comes to energy efficiency matters. We respect his opinion but hope he is wrong. We are assured by the builder telling us that they are not going to walk away from the problem. No doubt as part of the NHBC exercise some data monitoring will be needed in our house to assess the issue. However unless they move very quickly it will be difficult to collect much data before December 2016, as there is nothing wrong with the thermal gain of the house with the sun out. The approaching higher external air temperatures will also play their part.
To add insult to injury the study (bedroom) ceiling along with the distribution duct in the loft have not been insulated, some two months after we reported the insulation problem to the housebuilder and some three weeks after poor access prevented them from fully rectifying it. As I work I have had to put up with having cold air blown at me all winter long as air from the MVHR vent gets nicely chilled in the unheated loftspace. The thermal images show that air that should be at around 20°C is actually entering the study at 12°C. Not a great deal of thermal comfort there from a house that is supposedly built to high thermal and airtighness standards! The builder clearly does not feel it is an urgent issue so no doubt we will be well into the Spring before they get round to insulating it to the required standard.
I can only wonder how this got through their quality control, building control inspections and an NHBC sign off. It shows the lack of value that building certification has for a homeowner. It is not something to be relied upon at all. It does seem to give housebuilders something to hide behind; a little like VW diesel cars hiding behind European emissions testing results.
Update 12 January 2020: See Draught Problems: The Battle With The French Doors Part 3