Your client wants floor heating. Your name's on the drawings if it fails.
When a hydronic system underperforms, the client doesn't blame the plumber who laid the pipe. They blame the design – your drawings, your reputation. Hand it to engineers who take that problem off your desk: we do the calculations, our own crews install the system, and we carry the performance risk.
A Euroheat pipe layout before the pour. Once the concrete goes down, nothing in this picture can be changed.
A one-line floor heating note puts your name on the risk.
Most architects spec floor heating the way it's always been specced – a note on the drawings, left to the builder's plumber. Then one of the classic failures bakes itself into the slab: a suspended slab, no thermal break, a boxed-in heat pump, no heat-load calculation.
The client's floor never warms, or costs up to four times what it should to run, and the conversation about whose fault it is starts with your drawings.
You don't have to become a heating engineer to avoid this. You have to hand it to one.
What no design looks like, halfway through a $5 million build.
A real case from our files. Told as it happened; where a name is changed, we say so.
George is a Perth builder (name changed). Halfway through a ~$5 million house on the Swan River, the geothermal heating and cooling his client wanted from the start was with a company that used all the right words. Fourteen months in, he fired them. When we arrived on site, the design for a $429,000 system was a few emails and some coloured lines drawn over a PDF site plan.
Our calculations found the bore-field undersized by 41%, and seven heat pumps where one or two were needed. Salvaging what could be salvaged cost the owner $90,000 on top of the original contract – and some of the efficiency loss is permanent.
This is what happens when nobody runs the calculation.
What a standard install skips – and what your drawings can ask for.
| Standard install | Engineered first | |
|---|---|---|
| Heat load | Rarely calculated. Pipe laid to fill the floor. | Calculated room by room, system sized to real demand. |
| The slab | Pipe in an uninsulated slab, often no thermal break – up to 70% of the heat lost in the worst cases. | Insulated screed or thermally broken slab, detailed before the pour. |
| Thermal bridges | Ignored – double to triple the running cost. | Found and broken at every junction. |
| Heat pump siting | Wherever it fits – up to 50% efficiency lost. | Sited to breathe, designed into the plans early. |
| Who carries the risk | Whoever signed the drawings. | We do. Every room to temperature, or we fix it at our cost. |
Terms on this page: screed – the concrete-like layer the heating pipes are buried in, poured over the main slab; thermal break – a strip of insulation that stops the warm slab touching anything cold; thermal bridge – any place the warm slab touches something cold, so heat leaks out.
You keep the client. The risk comes off your drawings.
Hand over your client's floor heating requirement and it runs end to end from there. You stay the architect; the specialist behind you makes sure it performs – and the client thanks you for the recommendation.
The calculations, done
Room-by-room heat load, system design to The 37-Point Design, every detail your drawings need.
The performance risk, off your desk
The Comfort Guarantee: every room reaches its designed temperature, or we fix it at our cost. Not your liability – ours.
One team, design to commissioning
We design every millimetre, install it ourselves, and stand behind it. No coordination headache landing back on your desk.
A client who remembers it was your call
Your client gets a home that's warm, quiet and cheap to run – and remembers who recommended it.
Geothermal and fresh air – straight answers for the next project meeting.
Clients ask for geothermal because it sounds like the efficient choice. Sometimes it is. The honest cases are on one page – when it genuinely wins (pool heat recovery, noise-sensitive sites, Perth's ~20°C aquifer), when it never pays back, and the weakest-link rule that decides the bill either way.
Geothermal, Straight: When It's Worth the Money – and When It Isn't →
The other question that arrives late is mechanical ventilation. A sealed, well-insulated house needs fresh air brought in deliberately, and heat recovery ventilation does it without giving away the heating.
The detail that decides it is where the ducts run. A long bare duct across an unconditioned Perth roof space loses much of the recovery before the air reaches the room – a drawing decision, not a commissioning one.
Heat Recovery Ventilation, Straight: When It Earns Its Keep – and When It Doesn't →
Prefer to watch? Architects' guide to geothermal systems (24 min) → · Architects' guide to radiator heating (12 min) → · A tour of a geothermal system (21 min) →
Start with the pack – or send us the drawings.
The Floor Heating Spec & Risk Pack: what to put in your drawings, the failure modes to avoid, and who carries the risk if it's wrong. Got a live project with floor heating in it? Send your client to The Comfort Guarantee Roadmap – $1,450, 100% credited to the build – and the engineering, and the risk, become ours.