Most of India needs heating for a few weeks a year. The Himalayan belt needs it for five months and that single fact reorders every design decision we make. A system that's perfect for a Gurugram bathroom would be an expensive mistake in Manali. Here's how the mountains change the maths, drawn from a decade of projects between Srinagar and Gangtok.
Duty cycle decides the fuel
At a 100-hour heating season, hardware cost dominates and electric wins. At 2,500 hours, running cost dominates everything. That's why practically every whole-home system we install above 1,500 metres is hydronic, and increasingly heat-pump driven.
Modern air-source heat pumps hold useful output down to −15 °C, and a radiant floor is their ideal partner: because the emitter is the entire floor, the water only needs to reach 35–40 °C exactly the range where heat pumps are most efficient. The same machine feeding wall radiators would need 60 °C water and twice the electricity.
Thermal mass is a feature, not a bug
In plains bathrooms we fight for fast response. In the mountains, we want the opposite: a 65 mm heated screed that charges up during the day ideally on daytime solar generation and radiates through the evening. Several of our Himachal projects run the heat pump almost exclusively in daylight hours and coast to midnight on the slab's stored warmth.
A screeded floor is a battery you walk on. In the mountains we size it deliberately, like any other component.
Details that only matter when it's −8 outside
Cold-climate design is mostly a list of small disciplines:
- Insulation under and around. Perimeter strips matter as much as under-slab boards; an uninsulated slab edge bleeds heat straight into frozen ground.
- Glycol dosing for any pipe run through unheated spaces, checked at annual service.
- Room-by-room balancing. A south-facing room with mountain sun needs a fraction of the flow of a north bedroom; flow meters on the manifold make the difference visible.
- Backup heat source. We pipe manifolds so a small gas boiler can step in during a heat pump service redundancy is not optional at altitude.
The Cedar House numbers
Our longest-running hotel installation 22 rooms in Manali has completed two full winters on an AquaFlow screed system with twin air-source heat pumps. Season-long metering puts heating cost at ₹41 per room-night, roughly a third of the diesel-boiler estimate the owners were originally quoted elsewhere, with zero guest complaints about cold floors in either season.
If you're building in the hills, involve the heating design early pipe in screed costs a fraction of any retrofit, and the structure itself becomes the heating system. Talk to our design team before the slab is poured, and the mountains get much easier to live with.
Written by Arjun Mehta
Founder & CEO
Part of the ProWarm India team designing and installing radiant heating across the country since 2012. Meet the team.
