# Radiator Calculator Pro — Heat Output & BTU Calculator

> Calculate room heating requirements in Watts and BTU. (iPhone/iPad app by DigitalKind Ltd.)

- Source: https://appshunter.io/ios/app/radiator-calculator-pro/id6743349772 (this page in markdown: same URL + `.md`)
- Developer: [DigitalKind Ltd](https://appshunter.io/developer/1557937157)
- Category: Utilities, Reference
- Price: Free with in-app purchases (on sale, was $0.99)
- Age rating: 4+
- Requires: iOS 26.0 · 15 MB
- Languages: American English
- Released: 2025-03-17
- Data updated: 2026-08-13
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/radiator-calculator-pro/id6743349772/reviews.md

## What is Radiator Calculator Pro?

Room-by-room radiator sizing. Watts and BTU/h output for any room, factoring volume, glazing, external walls, roof and floor exposure, and insulation standard.

Calculation
Heat output per room with adjustments for:
• Room type (8 presets: bedroom, living room, bathroom, kitchen, hallway, office, conservatory, garage)
• Internal volume
• Window-to-floor ratio
• Number of external walls (0–4)
• What's above (loft, pitched roof, flat roof, heated space)
• What's below (garage, unheated cellar, uninsulated floor, heated floor)
• Insulation level: poor (older single-glazed) → average (modern build) → good → excellent (new-build, triple-glazed)
• Mean water temperature - ΔT30, ΔT35, ΔT40, ΔT50, ΔT60

ΔT correction uses the standard panel-radiator exponent (n = 1.30) per EN 442 testing convention. A 5% safety margin is applied to avoid undersizing.

Heat-pump systems

Select ΔT35 or ΔT30 to spec radiators for low-temperature systems. Output is rescaled — a 1000W ΔT50-rated radiator delivers ~630W at ΔT35 — so you size to actual delivered heat, not nameplate.

Output
• Watts and BTU/h side-by-side
• Metric or imperial dimensions
• Whole-home heat-loss total
• Share or export room specs as text

For plumbers, heating engineers, and heat-pump installers sizing radiator schedules, and homeowners or landlords running their own jobs.

## Key features

- Calculate heating requirements
- Support for all room types
- Precise Watts and BTU output
- Unlimited room saving
- Intuitive user interface
- Dark mode support

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Radiator Calculator PRO | $3.99 | one-time |


## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/radiator-calculator-pro/id6743349772/reviews.md

### 1/5 — Don’t bother

*2026-02-02*

No where near acurate

### 1/5 — Waste of £1.99

*2025-07-23*

A useless app, so basic and such limited options that’s it’s impossible to get a true heat loss. The idea works, each room added and listed on one platform for easy of sizing a house, it just lacks every detail to make it work.

## Frequently asked questions about Radiator Calculator Pro

### What is Radiator Calculator Pro?

Radiator Calculator Pro is a utility app designed to accurately calculate the heating requirements of any room. It provides precise calculations in both Watts and BTU, helping users select the correct radiator size.

### How much does Radiator Calculator Pro cost?

Radiator Calculator Pro is a paid application, available for a one-time purchase of $0.99. There are no in-app purchases or subscriptions required.

### Does Radiator Calculator Pro have ads?

No, Radiator Calculator Pro is ad-free. Users can enjoy a seamless experience without any advertisements interrupting their calculations.

### What devices is Radiator Calculator Pro compatible with?

Radiator Calculator Pro is available for iPhone and iPad devices. It is designed to work on Apple's mobile operating systems.

### How often is Radiator Calculator Pro updated?

The latest version of Radiator Calculator Pro is 1.3.1, last updated on February 4, 2026. Updates typically include improvements and new features based on user feedback and developer releases.

### Can I calculate heating for multiple rooms with Radiator Calculator Pro?

Yes, Radiator Calculator Pro supports unlimited rooms. You can add and customize any room type, saving and managing as many as you need for your projects.

### What age rating does Radiator Calculator Pro have?

Radiator Calculator Pro has an age rating of 4+. This indicates it is suitable for users of all ages, with no content restrictions.

### Does Radiator Calculator Pro offer dark mode?

Yes, Radiator Calculator Pro features dark mode support. This allows for a comfortable viewing experience in low-light conditions or personal preference.

## Version history (last 5 releases)

### 1.5 — 2026-05-15

Thank you for using Radiator Calculator PRO. We’re always improving the app with performance enhancements, bug fixes, and tweaks to make the experience even better for you.

### 1.3.1 — 2026-02-04

Refined the heating calculation to better reflect average UK homes.

### 1.3 — 2025-10-01

• Added full support for iOS 26
• Optimised performance and compatibility for the latest devices and system features

### 1.2 — 2025-06-18

iPad support is now available, featuring a layout optimised for larger screens.

This update also includes a few small refinements to improve the overall experience.

Thanks for your continued support and feedback. More updates coming soon!

### 1.1 — 2025-06-15

New update to make your experience even smoother.

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All apps by DigitalKind Ltd: https://appshunter.io/developer/1557937157

## Related topics

[electrace heat loss calculator](https://appshunter.io/ios/topics/electrace-heat-loss-calculator)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-13.*