kevinm

I interviewed for a position as a Site Engineer with the OPW 13/14 years ago. I have never come across such a group of ignorant and arrogant civil servants. Totally aloof, and out of touch, most joined straight out of Uni, and had zero private sector experience.

I would say zero difference. I doubt I will ever get the extra money spent on PH certification back.

Heat recovery drops with increased capacity, there is a strong trend to support this, look at the Zehnder/Helios/Brink units. The bigger units in a product family have lower heat recovery efficiency. The SB-350 achieves 79% heat recovery. The bigger SB-550 would be very close to the 75% minimum heat recovery requirement for PH certification. Maybe they dont want to risk the cost if they are not certain that it will pass? The PH-crtified Titon looks different to all the other HRV3 machines, the filter access is different. That suggests there is more than just the cost of certification at play, looks to me like they made a special unit targeting high efficiency.

I am going block and EWI, so cant comment on ICF. Most high-performimg MHRV units have PH certification now, I would be skeptical of any unit making big claims and not getting PH certification.

If you build the house to PH spec (use PHPP etc), the main extra cost is the external validation, which I have been quoted £2300.

He is travelling to me in Ennis, so I assume so.

Hillard Tanner He is doing the design for my passive-certified masonry build (insulated raft and EWI). He has a lot of experience in insulated rafts. He is based in Fermoy.

It's not just a lack of storage capacity but grid stability. Grids need the inertia form large spinning turbines to balance the grid as supply and demand fluctuates. PV inverters, dont have any inertia, and they also track the grid frequency, so they dont resist any frequency deviation. For this reason most grids need a mininum number of thermal plants to remain in production to provide inertia to the grid. There are now devices called synchronous condensors, which are basically enourmous flywheels connected to a motor/generator, that provide grid inertia for times of high renewables production. Google synchronous condensors.

I considered the same idea but decided against it. Air has such a low heat capacity, you need to move a lot of air (noisy) to get a decent cooling effect. Also any cooled ducts will need to be insulated to stop condensation forming in the void spaces (potential for mould of drips staining ceilings. I'm still waiting for the phpp calcs to be done, but I'll most likely be going independant MHRV and a few hidden splits in ceilings where needed.