# Radisize: Radiator Calculator — Room-by-room radiator sizing

> Room-by-room radiator sizing (iPhone/iPad app by Zippy IT Solutions Ltd..)

- Source: https://appshunter.io/ios/app/radisize/id6755719529 (this page in markdown: same URL + `.md`)
- Developer: [Zippy IT Solutions Ltd.](https://appshunter.io/developer/1841666879)
- Category: Utilities, Productivity
- Price: Free with in-app purchases (on sale, was $1.99)
- Age rating: 4+
- Requires: iOS 13.0 · 48 MB
- Languages: American English
- Released: 2025-11-26
- Data updated: 2026-01-13
- User reviews in markdown: https://appshunter.io/ios/app/radisize/id6755719529/reviews.md

## What is Radisize?

Radisize is the modern way to calculate the correct radiator size for every room in your home or project. Whether you are renovating, upgrading your heating system, or working professionally, Radisize gives you clear BTU and kW requirements based on real room details.

Simply add a property, enter each room’s dimensions, glazing, walls, and floor materials, and Radisize automatically calculates the radiator output needed at either ΔT35 or ΔT50. All calculations are done offline on your device.

FEATURES

• Room-by-room radiator sizing
Enter room type, dimensions, glazing and materials to get accurate BTU and kW requirements.

• Multiple properties
Create and manage as many properties as you need for your home, rentals, or client work.

• Guided room setup
A simple three-step wizard makes entering each room’s details quick and easy.

• Accurate BTU and kW outputs
Calculations use realistic heat-loss logic and your preferred radiator rating (ΔT35 or ΔT50).

• Customisable settings
Choose metres or feet, set your default ΔT, adjust the safety factor, and pick light, dark or system theme.

• Professional PDF reports
Export clean, organised reports for an entire property containing every room’s radiator requirement. Ideal for planning, quotes and documentation.

• Offline-first
No account, no internet, no data sent anywhere. Everything is calculated locally on your device.

WHO IT'S FOR

Homeowners and DIY renovators
Plan heating upgrades confidently, understand your home’s requirements, and choose the right radiators without guesswork.

Heating engineers and installers
Get quick on-site estimates, generate structured PDF reports, and keep multiple properties organised.

WHAT RADISIZE CONSIDERS

• Room dimensions (metres or feet)
• External wall count
• Wall construction type
• Floor and ceiling types
• Glazing area and window type
• Safety factor
• ΔT35 or ΔT50 radiator rating

Every detail is used to provide a more reliable radiator requirement.

Radisize offers a clean and modern design that makes complex heating calculations simple and approachable for everyone.

No subscriptions. No login. No hassle. Just fast, clear radiator sizing.

Use of this app is subject to Apple’s Standard Licensed Application End User License Agreement (EULA), available in the App Store under “License Agreement” and at https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ 
Download Radisize today and find the right radiator size for every room.

Disclaimer: Radisize provides estimation guidance only. Results are approximate and do not replace professional design or safety advice. Always consult a qualified heating engineer and follow local building regulations before purchasing or installing any heating equipment.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Radisize Pro | $2.99 | one-time |



## Version history (last 2 releases)

### 1.1.0 — 2026-01-12

This update introduces Radisize Pro, a one-time upgrade that unlocks unlimited properties, rooms and PDF export. It also includes performance improvements and bug fixes.

### 1.0 — 2025-11-27

No release notes.

## More apps by Zippy IT Solutions Ltd.

- [Baby Monitor Nanny Cam: Adarya](https://appshunter.io/ios/app/baby-monitor-nanny-cam/id6752904472)
- [TabPulse: Auto Tab Refresher](https://appshunter.io/ios/app/tabpulse/id6756150994)
- [Merge Voice Memos: StitchMemos](https://appshunter.io/ios/app/merge-voice-memos/id6756748944)

All apps by Zippy IT Solutions Ltd.: https://appshunter.io/developer/1841666879

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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 2026-01-13.*