Destratification Fan Energy Savings – The Performance Claims.
There are many manufacturers of destratification fans these days as people wake up to the
lost energy that lurks beneath their ceilings. But there is a problem – with so many products competing in the market for your custom, the technical and sales information being banded about is becoming fiendishly confusing. Some say that their destratification fan energy savings can as much as 20% of your heating costs, some say 30%, some even say 40 % savings.
So what is the truth of these claims and how do you compare different models?
The key advice here is to ignore completely the claims on destratification fan energy savings because they are all true…., in a sense.
Understanding Destratification Fan Energy Savings Potential
It is generally accepted that in rooms with stratified air, the temperature differential is typically 2-3°C per 5m hight, and as much as 1°C/m height. Taking the largest differnetial rate as an example, this means that in a 10m high room the difference between temperature at floor level and ceiling level can be 10°C. The simple truth is that the higher the ceiling the greater the potential temperature differential, and therefore the greater the likely savings from implementing effective thermal destratification fans.
How Do Destratification Fans Save Energy
The way the savings come through is that when the destratification fans are installed and switched on, air is destratified and the heating system can be set to a lower temperature. Lets assume you have a 10m ceiling and the objective is to heat to 18°C at experienced level.
Assuming 1°C/m as differance (for easy maths), then the air at the air at ceiling level could easily be 28°C. The average of these temperatures is 23°C. In order to achieve the 18°C target, the heating systems needs to work to achieve a 23°C average temperature. The theory is that the cost difference between heating to 18°C, and heating to 23°C is the potential saving that you can achieve, by using destratification fans.
Now whether that cost saving is 10, 20, 30 or 40% depends on a whole host of factors, but before discussing that it is worth reflecting that the potential cost saving increases as the ceiling height increases. What this means is that leaving aside the other factors in the potential savings equation, that is very unlikely that 40% heating cost saving will be achieved if your ceiling height is only 3.5m. If on the other hand you have 30m roof line ceiling then 40% heating cost saving is much more likely.
The other factors that determine the extent of the destratification fan energy savings include,
- Ambient temperature outside
- Materials of construction and how well insulated the building is
- The efficiency of the heating system
- The control accuracy of the heating system
- The actual temperature differential pre destratification
- The effectiveness of the destratification fans
- The running costs of the destratification fans
- The pricing structure of the running cost to your heating system
Soucing Destratification Fans? – A Little Advice.
So beware the destratification fan energy savings claims of the manufacturers, but instead endeavor to understand the source and factors influencing the potential savings. The key thing though is to select destratification fans based on their destratification performance and effectiveness. But before launching into selecting the destratification fan with the highest airflow in the belief that this is the measure of performance, please take a moment to read our guide on destratification fans, because it is not quite as straight forward as that.