Nestor

I am near completion of a timber frame new build ( 275sqm ) which just happens to meet Passivhaus Certification, I think a fee of £3k was mentioned earlier on a thread but I cannot find confirmation online. Maybe a useful sales consideration if the property is to be sold. Out total DHW and Heating (ASHP) requirement was 3891kWh over the past year. Heating about 2/3rds of that. I appreciate that figure is specific to our family needs. Insulation, air tightness and attention to detail were the contributing factors to our build.

I do agree with the above. Was just interested and you highlighted the position and location which does have a minimal impact on performance. Ours is southeast facing, about 35-40 degrees and has no shading.

We have a 3.74kW PV array and it produced 95 kWh in December and 109kWh in January. What is your average over the year?

I did spend half a day up at Tata for some basic training, no great detail. Without openings its very straightforward. You create an upstand on the Colorcoat panels to fit under the Velux flashing kit. Enclosed is the Tata Spec Guide, drawing ASU05 for Top Abutment as well as roof lights and drawings for a warm roof. It might be worth getting quotes from professionals as it is a small roof, I had 300 sq metres so the savings were considerable. Specification-Guide-Tata-Steel.pdf

Yes , it is possible. I have a similar timber frame build, air tight, 3G glazing, ASHP, UFH, MVHR and budget with minimal building experience. However, the only professionals hired were plasterer, electrician, ground floor screed, install of ASHP and commissioning for RHI and some minimal plumbing. If you can do the rest from groundworks up to the roofing and plenty of time, 3 years + go for it.

You will need 3 tools to fit the Tata / Catnic, listed below. I also purchased a metal blade for a circular saw. Its straight forward to fit, nailing strip on one side and hit with a hammer and block of wood the other. I had 300 sqm to fit and 7 Velux to fit round which was a bit of a challenge. You might find the delivery charge is more than the product. 1 EAVES CLOSER CU094300 Tools 2 STUBAI PLIERS CU094200 Tools 3 FLANGE MATE CU094400 Tools

I have recently built a new house which by chance meets the below Passive House specification , I did not set out to meet the specification but due to the amount of insulation, MVHR, PV, 3G windows and an ASHP it could be referred to as a Passive House spec without the certification. https://passiv.de/en/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm Passive House requirements For a building to be considered a Passive House, it must meet the following criteria ( for detailed criteria, please see the building certification section): 1. The Space Heating Energy Demand is not to exceed 15 kWh per square meter of net living space (treated floor area) per year or 10 W per square meter peak demand. In climates where active cooling is needed, the Space Cooling Energy Demand requirement roughly matches the heat demand requirements above, with an additional allowance for dehumidification. 2. The Renewable Renewable Primary Energy Demand (PER, according to PHI method), the total energy to be used for all domestic applications (heating, hot water and domestic electricity) must not exceed 60 kWh per square meter of treated floor area per year for Passive House Classic. . 3. In terms of Airtightness, a maximum of 0.6 air changes per hour at 50 Pascals pressure (ACH50), as verified with an onsite pressure test (in both pressurized and depressurized states). 4. Thermal comfort must be met for all living areas during winter as well as in summer, with not more than 10 % of the hours in a given year over 25 °C. For a complete overview of general quality requirements (soft criteria) see Passipedia.

We have never run out of hot water, probably happen now.... due to the capacity of the cylinder. The DHW is always on, not timed unlike the heating. We had a few families visit last summer and no one mentioned a lack of hot water. Presently we have another adult lodging with us. On sunny days the tank is usually back up to temp via the PV diverter by 10am during the summer. I guess the next size up is 400L.

We were spending the same amount on oil in our old 100 sqm bungalow, damp and mouldy and very cold in the winter.

We have an 8.5kW Ecodan with 300L UVC. 3.74kW of PV and a solar diverter. 285sqm / 750m3 new self build, ugh, air tight with MVHR. The ASHP has used 4100kWh in the last year to provide heating and hot water for a family of 4 adults. 4 + showers a day, occasional bath, daily washing up and have had heating on in only 3 out of 14 rooms. Homeowners being encouraged to adopt the new (old) technology are in for cost shock but that is probably due to the quality of the build and the price for that specific unit of energy. But maybe that is part of the plan...still using lots of gas at the CCGT plant.

Supply and extract on same external wall. 2.5m apart, extract 1.5m higher. Never had any cross contamination. Fine mesh supply clogged after 9 months.

Have the same unit fitted so much appreciated. Have bookmarked.

@Adsibob Never turned it off. Our MVHR runs 24/7, barely noticeable in the background unless on boost. You can set the supply, extract and boost speeds. Minimal condensation in the bathroom after having baths or long showers but clears quickly. Probably down to airtightness, quality of windows (3G) and overall build quality.

@Adsibob I used 40mm Pavatherm to cover all the walls and roof. Then 265mm and 275mm of Rockwool in 3 layers. Drawing enclosed. Floor, Wall, Roof Build up Jan 2018..pdf

I fitted Pavaflex above the rafters, a warm roof and would recommend as much as possible. As @Russell griffiths says, rafter size limitation as well as your maximum external heights.

@ProDave Well done so far. I hope to do same but with 285 sqm + 72 sqm garage.It just takes time, nearly 4 years so far! Does your cost include VAT?

Quick update as perhaps why the MVHR was not quite meeting the supply demand. I recently removed the external inlet grill and this what I found. Will retest the ventilation rates now.

No knowledge of Ubbink but I recently removed the inlet grill to fit cedar cladding and quite surprised at the amount of rubbish in the grill. This was after only 8 months. So access for cleaning quite important.

You have had help from others, I used the spaces, only 3 as I was fixing a 10mm x1000mm x 2000mm screen onto the wall and shower tray. I then siliconed once in place. If the screen is already fixed to the wall and not slipping down just fill with silicon.

Try here: https://www.wholesaleglasscompany.co.uk/acatalog/Transparent-Plastic-setting-and-Distance-Blocks.html

My only concern is where is the Pantry? Someone will be along to advise. HNY.

Sorry I meant just change the existing flow and return manifold first before spending money.

I would just swop over the manifolds as Peter and Nick have suggested. Isolate the two manifolds. You will have to top up the loops and purge the air, Wunda has all the details.

Same in the roof. Foundation is 100mm concrete, 150mm Celotex, 40mm screed. Figures below are for just over 10 months.

Yes that includes DHW. Stick built timber frame, From the outside : Cedar cladding, Counter batten, Batten, Breather Membrane, 40mm Pavatherm, 260mm Rockwool cross layered, VCL, OSB, Batten, Plasterboard, Skim.