# Heatloss Calculator & Guide

> Calculate heat loss, radiator output, and energy conversions for home heating. (iPhone/iPad app by Mr Combi Training.)

- Source: https://appshunter.io/ios/app/heatloss-calculator-and-guide/id620793018 (this page in markdown: same URL + `.md`)
- Developer: [Mr Combi Training](https://appshunter.io/developer/566867832)
- Category: Productivity, Utilities
- Price: $4.99
- Rating: 1.50/5 from 2 App Store ratings · 15 written reviews indexed
- Age rating: 4+
- Requires: iOS 11.0 · 2 MB
- Languages: American English
- Released: 2013-04-24
- Data updated: 2026-09-04
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/heatloss-calculator-and-guide/id620793018/reviews.md

## What is Heatloss Calculator & Guide?

The Heatloss Calculator & Guide from Mr Combi Training includes three useful calculators:

• Heatloss calculator - finds the heatloss from a room
• Radiator calculator - estimates a radiator's length/output
• Converter - quickly converts between Watts and BTU/h

Heatloss Calculator:
This easy to use calculator lets you enter the details for a room, with dimensions in metres or feet, and it will then will calculate the heatloss in Watts and BTUs per hour. The desired room temperatures (12 - 24°C) can be set in the settings page and also the outside temperature (-30 to +5°C) the temperatures are also given in their Fahrenheit equivalents.

The results will show:

• Ventilation heatloss - Losses from air passing through the room.
• Fabric heatloss - Losses through walls, floor and ceiling.
• Total heatloss - Sum of the ventilation and fabric losses.

The required radiator for the room can then be determined from the total room heat loss i.e. select a radiator that's rated higher!

The app can also be used to work out how much could be saved by fitting double glazing, cavity insulation or extra loft insulation to your home. Carry out a survey of each room in your house, with and without the double glazing/cavity insulation/loft insulation, then total the differences for the whole house to find how much heat is being wasted.

The app will even also calculate the time taken to heat the room from the set outside temperature if the right radiator is fitted. You can also enter flow and return rates and the Mean Water Temperature (MWT) and Delta T will be calculated, making it easier for you to select the right radiator using the manufacturers correction factors.


Radiator Calculator:
This calculator will estimate the length or power output from an existing compact radiator using a range of calculations from the most popular radiator manufacturers in the UK.

To find the output you simply select the radiator type, select the height, enter the length (in mm or inches) and select the Delta T. The results will then show the lowest and highest power outputs from across the different manufacturers and then the average will be calculated. This is very useful if you want to show a customer that their radiator is too small for a room.

To find the estimated length select the radiator type, select the height, enter the output and select the Delta T. The results will then show the estimated length the radiator would need to be.

The following radiator types are supported:
• P1 - Single panel
• K1 - Single convector
• P+ - Double panel
• K2 - Double convector
• K3 - Triple convector


Email, Save or Export:
Once you have your results you can email them directly from within the app, save them to your device or export them to another app that supports text files, such as Dropbox, Google Drive or Evernote.

You can also use the saved results to add up all the heatlosses from a house so you can find the total heating load.


Converter:
The super simple Converter will help you quickly convert between Watts and BTU/h. Just enter one value and the other will be calculated.


Guide:
To give you some extra help when you need it, we have added a mini-guide to the Radiator Calculator with the following 4 pages:
• Correction factors - Shows you when and how to apply a correction factor to your results
• DeltaT Calculations - How to calculate the MWT and DeltaT
• Common Faults - Lists a number of common radiator faults, their symptoms and remedies
• Balancing - Instructions for balancing a system

## Key features

- Room heat loss calculation
- Radiator output estimation
- Watts to BTU/h conversion
- Energy saving analysis
- Radiator sizing
- Save and export results

## Recent user reviews (10 of 15)

All indexed reviews: https://appshunter.io/ios/app/heatloss-calculator-and-guide/id620793018/reviews.md

### 1/5 — Terrible app

*2023-12-11*

App is inaccurate and everything is in Celsius and MM. waste of $5

### 2/5 — Site address results

*2023-06-14*

Need the option to group all the results of a property into one file and allow printing , e mailing .
At moment have to save each room separately.

### 1/5 — Can’t add windows as per other reviews

*2022-11-21*

Heatloss options very limited on insulation. Better than nothing but not much better.

### 2/5 — Great ideas and easy to use but missing options

*2020-08-28*

Would love to see other wall type and insulation type options added. 

Eg solid stone walls missing from list. 

Then an ability to add insulation depths to see impact on heat loss.

### 1/5 — NOT WORTH IT

*2018-11-06*

Surprised Apple allow this app on its store.
Does not allow you to add rooms
Can’t email even a single rooms result
Does not do what it says on the tin.

**Developer response:** Hi SolarMan, we're sorry you're unhappy with your purchase. The app does indeed do everything as written in the app description, you can calculate the heatloss of a room, you can save the results, you can email the results and you can even calculate the total heatloss for multiple saved results. If you need any help with using the app then don't hesitate to get in touch.

### 1/5 — Very limited

*2018-05-08*

Can only calculate one room at a time and does not accumulate 
Not worth it
Freebies out there do more

### 5/5 — Great apps

*2017-10-04*

Great apps stops me worrying about ACS

### 1/5 — No

*2016-04-21*

Very basic, not happy with this purchase, I want my money back.

### 1/5 — Very limited

*2016-03-31*

Very limited on what the heatloss calculator does. Basic information and no accumulated heatloss calculations associated with one property consisting of all rooms.

### 3/5 — Mr.

*2016-02-08*

There is an error in heat loss calculation, comparing the total windows area with that of a wall area. It gives an error message even if the window area is less than 30% of the wall area and hence crashes.

## Frequently asked questions about Heatloss Calculator & Guide

### How accurate is the Heatloss Calculator & Guide?

The app provides calculations based on user-inputted room dimensions and temperatures. It offers detailed breakdowns of ventilation and fabric heat loss, and estimates radiator output based on popular UK manufacturer calculations. User reviews indicate a 1.5-star rating from 2 ratings, suggesting potential areas for improvement in accuracy or user experience.

### What is the price of Heatloss Calculator & Guide?

Heatloss Calculator & Guide is a paid app, priced at $4.99. There are no in-app purchases or advertisements, offering a one-time cost for full functionality.

### Does Heatloss Calculator & Guide have ads?

No, Heatloss Calculator & Guide does not contain advertisements. It is a paid application that provides an ad-free experience for its users.

### On which devices can I use Heatloss Calculator & Guide?

Heatloss Calculator & Guide is available for iPhone, iPad, and iPod touch devices. It is designed for iOS users looking for heating calculation tools.

### How often is Heatloss Calculator & Guide updated?

The app was last updated on April 19, 2023, with version 3.0. This indicates a recent update, suggesting ongoing support and potential for future improvements.

### What is the age rating for Heatloss Calculator & Guide?

Heatloss Calculator & Guide has an age rating of 4+. This means it is considered suitable for children aged 4 and above, with no mature content.

### Can I export my calculations from Heatloss Calculator & Guide?

Yes, you can email, save, or export your calculation results directly from the app. This allows you to share your findings or store them for later use in other applications like Dropbox or Google Drive.

### What are the temperature ranges supported by Heatloss Calculator & Guide?

The app allows you to set desired room temperatures between 12 and 24°C, and outside temperatures from -30 to +5°C. Both Celsius and Fahrenheit equivalents are provided for these temperature settings.

## Version history (last 5 releases)

### 3.0 — 2023-04-19

We have updated this version to load the APP quicker on most devices

### 2.9 — 2018-12-05

We've made some small tweaks for iOS 12.

### 2.8 — 2016-06-05

For our friends in colder climes we have reduced the minimum outside temperature to -30°C (-22.0°F). Brrrr!

### 2.7 — 2016-03-03

You can now enter a manual U-Value for external walls

### 2.6 — 2015-08-19

We've listened to your feedback and we've now added quite a few new options for heat loss calculations.

Also, just like our other fantastic apps we've added those handy little buttons for when you're entering data.

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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 2026-09-04.*