My Comfortline heat pump is only rated to 0°C, so I tested it heating my hot tub at -4°C. It was about 4x quicker and around two-thirds cheaper than my old 3kW heater.
DIY Hot Tub Building, Materials and Construction Related
Hot Tub Tiles: Mosaics, Porcelain vs Ceramic, Slip Resistance and Grout
09
Dec
Dec
Not all tiles are suitable for a hot tub. Here’s which to use, why I’d choose mosaic pool tiles, how porcelain and ceramic differ, and how to keep steps from being slippery.
08
Dec
Dec
The Vian Power heat pumps are built for UK and European hot tub retrofits. Here’s how the C5, C5 Plus, S7 Plus and S9 Plus compare, what the COPs down to -10°C really mean, and which to choose.
07
Dec
Dec
My Comfortline heat pump iced up at -2°C but kept heating. Here’s why heat pumps frost over, how the defrost cycle works, and how to force a manual defrost on a Comfortline.
DIY Hot Tub Building, Materials and Construction Related
DIY Hot Tub Insulation: What to Use and Where It Goes
01
Dec
Dec
Insulation is one of the cheapest ways to cut your hot tub running costs, as long as you do it while you build. Here’s what to use and where it goes for ICF, block, poured concrete and stock tank tubs.
25
Nov
Nov
The Onda Mini is a plug-in air source heat pump for hot tubs. Here’s how it performs, why it’s a warm-season unit, how to connect it, and whether it’s still worth buying in 2026.
24
Nov
Nov
TubBlox are ICF formwork blocks for building insulated hot tub and pool walls. Here’s how they work, what they need, the step-by-step build and the honest downsides.
21
Nov
Nov
How jets work in a DIY hot tub, which types to choose, why internals only swap within one series, and how to work out how many jets your pump can run.
Design / Ideas Related, DIY Hot Tub Building
What Makes a Good DIY Hot Tub Design? Sizes, Seats, Heating and More
11
Nov
Nov
The decisions that make a good DIY hot tub design, including the seat and water depths I design to, heating, the control room, safety and common mistakes.
Design / Ideas Related, DIY Hot Tub Building, Stock Tank Hot Tub
DIY Hot Tub Kit: What’s Included and Which One You Need
09
Nov
Nov
What’s in my stock tank and cedar/wood hot tub plumbing kits, which one suits your build, and what to use instead if you’re building an in-ground tub.