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Heat Loss Calculation - The Guide To Calculating Heat Loss

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01 September 2014

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Need to calculate heat loss? Read our guide from Powrmatic’s very own Tony England on everything you need to know about heat loss calculation for a building.

To enable a heat loss calculation to be carried out, for the selection of heating equipment, the details of the building and the full heating design requirements will need to be known. These are sometimes provided in the form of a consultant specification, especially if the project is a new build, or it might be necessary to carry out a site survey.

The heating requirements are determined by:

  1. Dimensions of the space to be heated – length, width and height (to eaves and ridge if a pitched roof).
  2. Dimensions of doors, glazing and roof lights (where applicable).
  3. Outside and inside design air temperatures.
  4. Ventilation rate, either natural infiltration or mechanical ventilation. If the latter, either the air volume flow or air change rate within the space.
  5. U values of the building fabric elements (preferable), or a description of the building construction. Failing any of these being known, the year of construction might give an insight into the U values based upon the Building Regulations at that time.
  6. Building usage/heating patterns (especially if usage is intermittent).
  7. Any significant heat gain(s) within the space(s)

During a survey it is also a good time to consider the following:

  1. Type of fuel or heating medium available, e.g. oil, gas, LPHW (water flow and return temperatures), steam (pressure).
  2. Warm air or radiant heaters.
  3. If warm air, the preference for either floor standing or high level/suspended heaters.
  4. If warm air, the potential benefits of destratification fans.
  5. Any dusts, gases, vapours or activities that might preclude the use of heaters inside the space.

Smart phone displaying Heat Loss Calculator app

The new Powrmatic Heat Loss Calculator App is a great way to instantly calculate the heat loss of any rectangle building. Its free and available to download at the following App centres.

Android app on Google Play logo      

Apple Store Download   

Google Play Store Download

These 12 points will ensure your inquiry into Powrmatic will can be dealt with quickly and efficiently. Once you can answer as many of the above questions, contact our sales office on 01460 53535 and our sales team will be happy to assist your your inquiry.

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