Heat loss calculation software
Size every room correctly in seconds. Vento runs a room-by-room heat load as you survey — accounting for glazing, orientation, insulation and occupancy — then selects the right unit and carries the result straight into the system design and the customer's proposal. No separate calculator, no re-keying.
Sizing that flows into the whole job
- Room-by-room heat loss and cooling load, instantly
- UK / CIBSE design conditions you can set
- Glazing, orientation, insulation & occupancy
- Correct unit selection from a SEER/SCOP catalogue
- Multi-split system sizing across rooms
- Result carried into design and proposal automatically
Frequently asked questions
What is heat loss calculation software?
It works out, room by room, how much heat a property loses in winter and gains in summer, so each room gets the right capacity rather than a rule-of-thumb guess. It takes the room's dimensions, glazing, orientation, insulation and occupancy and returns the kW each room needs. Vento does this automatically as you survey, then carries the result into unit selection, system design and the proposal. Americans call the cooling version Manual J; in the UK the same job is done to CIBSE design conditions.
Does it use UK design conditions?
Yes. Vento uses UK winter design temperatures and lets you set your regional conditions, so the sizing is right for British homes rather than a US default. It sizes equipment: where a job needs an MCS heat loss calculation for a grant scheme, that is a separate requirement and Vento does not replace it.
How is this different from a rule of thumb?
A rule of thumb (e.g. 0.1–0.15 kW per m²) ignores solar gain, insulation and occupancy — two same-size rooms can need very different units. A proper room-by-room load accounts for each factor, so you don't under- or over-size. Try it free on our air-conditioning size calculator.
See also: air conditioning software, how to size air conditioning, and F-Gas software.
Size every room automatically
Room-by-room heat loss built into survey, design, proposal and payment — one platform for the whole job. 14-day free trial.
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More of what Vento does
One platform — these are the parts of it installers ask about most.
- Air conditioning softwareThe whole job: survey, design, quote, e-sign and get paid.Read more
- Installer softwareBuilt for engineers on site, not adapted from a generic trade CRM.Read more
- Quoting & estimatingPriced from the survey, with your own materials and margins.Read more
- Proposals & e-signBranded documents with drawings, signed on the customer's phone.Read more
- F-Gas & logbookRegister, CO₂e totals and leak-check intervals, kept current.Read more