The life & times of an HVAC Engineer

My husband and I are currently trying to buy our first house together, so we spent this weekend looking at houses. By the end of the weekend we’d chosen the house we’ll hopefully manage to buy and we’d discovered that we truly are construction & energy geeks.

Whilst the estate agent showed us around, pointing out the ‘delightful neutral décor’ or the ‘brand new carpets’ or occasionally, at their peril, a room that ‘would be perfect as a nursery’ James and I were ferreting around checking the energy performance and pondering what energy-efficient upgrades we could make.

Of course the compulsory energy performance certificates (EPCs) are a big help these days, they let you know all the basic details about standards of construction, insulation and heating. They also tell you a few areas you could make improvements in, for example a fairly standard EPC comment is ‘install energy efficient light bulbs’. But EPCs are intended for the general public to understand and be able to act on…they wont give you the full potential of what could be achieved.

So, with heads stuck in loft space, peering through ventilation bricks and stomping over gardens we discussed a variety of ‘new’ technologies we’d consider installing in any of the 1930-1950’s houses we were looking at. A couple of our favourites were:

– A ground source heat pump coupled with underfloor heating. This would reduce the energy bills, and by using this heat we could actually gain money from the Renewable Heat Incentive. It would also mean we wouldn’t need any radiators so we’d gain floor/wall space, and they’re something rather lovely about pottering around barefoot on a heated floor in my opinion.

– A mechanical heat recovery ventilation unit, these draw hot, humid air from areas like kitchens and bathrooms and use it to heat fresh air from outside before delivering it to other rooms like bedrooms and lounges. Most houses lose heat through bathroom fans and kitchen extract hoods, and many houses have no fresh supply except through leakage which reduces as we install better doors and windows. People need oxygen to live and generally 8-12 litres of fresh air per second is recommended to be supplied to occupied rooms in order to keep people feeling awake and comfortable. So, instead of losing the heat from the kitchen, we would be re-using that heat whilst still getting nice fresh air into the building, like this:

With so many ideas bouncing round in our heads we can hardly wait to get into a new house and start saving energy!


In my attempt to drag my recession-sodden career onwards and upwards I do my best to take on new challenges and take ownership of my part of a project wherever I can. Late last week was a perfect example of that, and now I suddenly find myself responsible for the ‘consequential improvements’ for the project I’m working on. I’m not quite sure how it happened, but none-the-less it did and I’m rather pleased.

The ‘consequential improvements’ (or CI) are a particularly gratifying bit of the project to be part of in my opinion. Contrary to popular belief that’s not because I’m especially fond of long words & tongue twisters, it’s because CI is all about energy savings, and I’m a big fan of sustainability.

As of 2006 Part L of the building regulations means that if you change or extend a building over 1000m2 in the UK you must spend at least 10% of your budget on making the existing building more energy efficient. That could be anything from installing solar panels, to upgrading the windows to have a better level of thermal insulation to using the waste heat from an industrial process to heat the offices, the canteen kitchens or even changing processes to eliminate the heat use altogether! I think this is a brilliant way of changing our energy gobbling grey 1970s monstrosities that we don’t have the funds to replace into lean green manufacturing machines.

So at the moment I have about £300,000 to spend, and I’m researching a huge variety of different energy saving possibilities. So far I’ve looked at using heat recovery from the compressed air, as typically 80-93% of the electricity used in compressed air is ‘wasted’ by being converted into heat, and compressed air often accounts for around 40% of a plants electricity bill – that’s a lot of wasted electricity! I’ve also been looking at using variable speed drives, these mean that when you don’t need all of a service such as hot water, steam or compressed air you can turn down the machine generating it and use less power. Think of it like using a dimmer switch to get just the right amount of light – if the light isn’t on full you’ll be saving electricity. I’m also looking at economisers, which use the heat in the exhaust gases of a boiler to pre-heat the water coming in, as well as energy efficient lighting, improved insulation and many other options.

Considering that part of the reason that manufacturing has reduced in the UK is not just labour costs but also energy costs – perhaps Part L and the Consequential Improvements (said like that it almost sounds like a band name) will not only help to save the planet but will also help to save engineering in this country!

et cetera
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