Nick: A Promise, A SIPs Panel, And A Quiet Heat

A new build on the South coast. Heat pump, MVHR, skirting board heating. The kind of specification you arrive at when you take the questions seriously.

There's a moment in most heating conversations where the homeowner says something the industry isn't really set up to answer.

For Nick, the moment came years before the house was built. He turned to his wife and promised her she would be warm in later life.

That's not a brief most heating engineers know how to respond to. It isn't a U-value, a flow temperature, or a SAP score. It's a quiet, serious promise about how a house should feel for the next thirty years. The kind of promise that quietly governs every decision that follows.

“I did promise my wife, I don't know if I should have done this, that I would make sure she was warm in later life.”

Most renovation and self build stories begin with a brochure. This one began with a sentence said out loud and meant.

The House

The house is a six panel SIPs kit build, finished with an air source heat pump and an MVHR system. The three components are usually specified together because they're designed to work together. A well sealed structure, mechanical ventilation with heat recovery, and a low temperature heat source. On paper, it's about as close as the volume housing market gets to a Passivhaus aspiration without actually being one.

What the three components don't decide for you is how the heat actually gets into the rooms.

That decision sits with the homeowner. And for most self builders, it gets made quickly, at the back end of a long programme, often in a hurry, usually defaulting to underfloor heating downstairs and radiators upstairs. The same compromise we've covered before. The same compromise most kit house buyers don't realise they have a choice about.

Nick made his decision the long way round.

The Wells Visit

When you're spending six figures on a building, an hour spent in someone else's finished version of it is the highest leverage hour you'll have in the whole programme. Nick took it.

“We did actually go and look at one of the houses they built in Wells. I asked because I didn't notice any radiators, and I said have you got underfloor heating? And the lady said no, we've got skirting board heating. I'd never heard of skirting board heating, so I said, you happy with it? And she said, we love it.”

That's the marketing the heating industry can't buy. Not a brochure. Not a CGI. A homeowner standing in her own living room two years into the system, telling a stranger she loves it.

Nick is too analytical to let one conversation settle the question. He went away and researched it. Looked at alternatives. Read up on heat pump compatibility, because the air source heat pump was already specified and any emitter he chose was going to have to live at low flow temperatures. Then, two years later, he went back to the same homeowner and asked her the same question.

“I contacted the same lady two years later and asked her if she was still happy with the skirting board heating. And she said, my answer hasn't changed. We love it.”

That's a stress test you can't engineer. A two year gap, an unscripted return visit, the same answer. At that point, the spec was effectively decided.

What He Was Actually Buying

The thing Nick was solving for, underneath all the research, was a specific concern about how a house ages with its occupants.

Joints stiffen. Bedrooms get colder to walk into. Bathroom floors become hostile environments first thing in the morning. The radiators that used to be invisible become objects you navigate around, knock into, struggle to clean behind. The tall column rad in the spare room that nobody questioned for fifteen years becomes a hazard.

“We all have joints that ache when we're older, I do and my wife does to a certain extent. So it's nice to know we've got a house that we can move around freely.”

The conventional answer to that brief is underfloor heating throughout, because underfloor heating delivers gentle, even, ambient warmth at low flow temperatures, which is exactly what an air source heat pump wants to provide.

The problem with underfloor heating throughout, on a SIPs build, is that you're committing to a single emitter strategy across two storeys, with the floor build-up implications that come with it, and a system that takes hours to respond to changes in conditions. On a coast where the weather is famously volatile, that lag matters more than people realise.

“The weather conditions here are very changeable, even in the summer. We can have sunny, mild, calm weather and then suddenly two o'clock in the afternoon we have winds coming in, a shower coming in. The weather changes, the temperatures change.”

A heating system that takes four hours to respond to weather it didn't see coming is a heating system that's always either slightly behind or slightly ahead. ThermaSkirt sits at the other end of that spectrum. Low water volume, fast response, room reaches target temperature in twenty to thirty minutes rather than hours. The heat pump can run gently and continuously at low flow temperatures, and the emitters can keep up with whatever the South coast decides to do that afternoon.

That's not an obvious advantage on a brochure. It is an obvious advantage on a Tuesday in March when the wind has just turned.

The Process

The reason Nick didn't have to project manage the heating spec himself is that the manufacturer and the plumber actually talked to each other. This sounds basic. On a self build, it almost never happens.

“The sales team at DiscreteHeat were really good, and I encouraged them to speak to the plumber. Two way communication, that really worked well. They did all the hard work between them.”

What landed on the plumber's desk wasn't a box of components and a diagram. It was a colour coded floor plan showing exactly where the pipework needed to run for every room on every floor. Carl, the plumber, knew where to put the first fix pipework before he started, which meant the first fix was clean, fast, and right first time.

“I got copies of the actual layout of the floor plans and where the pipes were required. They were colour coded, so when it came to actually putting down the pipe work for the heating, it was very, very easy to do.”

When the install began, it stayed ahead of programme. Nick was given a tour of his own house at the point most homeowners are still being told we'll let you know when it's done.

“Carl stopped everything. He was well ahead, doing really well with the installation. He took me upstairs, started in the bedrooms, showed me everything he'd done, how the connections were, gave me a very confident timescale for the whole installation. He never not answered a question. It was always straightforward and to the point. I found him really approachable and easy to get on with.”

There's a tone in that quote that's worth pausing on. Nick is a careful, analytical homeowner. The thing he repeatedly notes about both the manufacturer and the installer is that they answered his questions properly and let him stay in control of the decisions. For a homeowner who has spent two years researching the spec, being treated as the most informed person in the conversation is the thing that builds confidence.

“From the first time I contacted DiscreteHeat, I felt they had my back. They weren't pushy at all. I was in control. I asked the questions, and at no time did I have any concerns.”

Living With It

The house is finished. The heat pump runs gently. The MVHR runs continuously. The skirting boards hold a low, even temperature along every wall. And Nick, in his own words, walks around the house in socks.

“I'm walking around in socks in here and it's great. I really, really pleased, as is my wife, with DiscreteHeat and the heating system we've got. It all goes together well with the rest of the system.”

The first morning in a new build is a moment most self builders remember sharply. It's the moment the spreadsheet meets the reality. Two years of decisions either land or don't.

“When we had our first night in this house and we came down in the morning, me for a cup of tea and the wife for a coffee, we sat down and looked out. It was just incredible to have had that journey through the house not even noticing the temperatures. There was no chill, no nothing. And that for me really made this house. It's made it a really special place to be.”

Not even noticing the temperatures is the highest possible compliment for a heating system. The whole point of heating is to make the absence of cold disappear. A system that requires you to notice it, manage it, balance it, defrost it, or live around it has failed the brief on some level. A system that quietly does the job and lets the homeowner pay attention to the view is doing exactly what it should.

The Specification Question

There's a wider point here for anyone specifying a SIPs or timber frame kit build with a heat pump.

The heat pump is going to dictate the flow temperature. The MVHR is going to handle the ventilation. The fabric is going to do most of the heat retention work. The emitters are the last component most self builders think about, and they're the component that determines what the house actually feels like.

Get the emitters wrong and the heat pump runs harder than it should. The rooms feel uneven. The cold downdraft from the glazing finds your feet. The lag between weather change and indoor response stretches out. Every other component in the system is compensating for the emitter choice rather than working with it.

Get the emitters right and the system disappears.

Nick's house is, on paper, a fairly conventional new build heat pump specification. In practice, it's the version of that specification where every component does its job and lets the next component do its job, with no compromises hidden in the floor build-up or behind the bedroom door.

Two years of research, two visits to a stranger's living room, and a quiet promise to his wife. That's how you arrive at a heating system you don't notice you're using.

Which, in the end, is the only metric that matters.