Frequently Asked Questions

EndoTherm is a unique, multi-award winning energy saving additive independently proven to save up to 15% on space heating energy consumption.

Below are some of the common questions asked about EndoTherm:

How Much EndoTherm Do I Need?

Commercially 1 litre per 100 litres of system volume. Experts from Endo Enterprises can calculate exactly how much EndoTherm will be required to maximise the potential return on investment.

Domestically The following table can be used to determine the expected EndoTherm volume requirement by property type & build form:

Property Type Build Form Expected EndoTherm Required
House Detached 1+ Litres
House Semi-Detached (3 bed plus) 1 Litre
House Semi-Detached (1 – 2 bed) 500ml
House Mid Terrace (3 bed plus) 1 Litre
House Mid Terrace (1 – 2 bed) 500ml
House End Terrace (3 bed plus) 1 Litre
House End Terrace (1 – 2 bed) 500ml
Flat Apartment (3 bed plus) 1 Litre
Flat Apartment (1 – 2 bed) 500ml
Flat Penthouse 1 Litre
Flat Studio 500ml
Maisonette Two-Storey (3 bed plus) 1 Litre
Maisonette Two-Storey (1 – 2 bed) 500ml
Maisonette Single-Storey 500ml
Bungalow Detached (3 bed plus) 1 Litre
Bungalow Detached (1 – 2 bed) 500ml
Bungalow Semi-Detached (3 bed plus) 1 Litre
Bungalow Semi-Detached (1 – 2 bed) 500ml
Bungalow Mid Terrace 500ml
Bungalow End Terrace 500ml
Park Home Double Park Home 1 Litre
Park Home Single Park Home 500ml

These guidelines are based on steel flat panel radiators, more EndoTherm may be required if higher water volume heat emitters like traditional cast iron radiators.

If you have any concerns about how much EndoTherm you may require please contact us for assistance.

Does EndoTherm work in any heating system?

Yes, any heating system where a boiler is used to heat water EndoTherm will work

How long does EndoTherm last?

EndoTherm will remain in a closed heating system without any deterioration of energy savings for at least 7 years, according to tests. EndoTherm must remain present and not be lost by drain downs, leaks or any other loss of system fluid. 

How do I install EndoTherm?


EndoTherm is installed at 1% of total system volume using the same methodology as traditional corrosion inhibitors and glycols. This is often through pre-existing pot feeders or pumped through valves. EndoTherm has a network of service partners in the US & Canada. Contact us to find out more.

Does EndoTherm need to be re-installed after a drain-down, for instance when the property is void, or when new radiators or a boiler are installed?

Yes. EndoTherm will need to be re-installed after a drain-down, or if the radiators or boiler are changed.

Should EndoTherm be applied to a clean or existing filled system?

EndoTherm performs both on an existing system with clean or dirty water and also on a new clean system. On a clean new system that has just been installed you will need to flush first before installing EndoTherm. From the various installations the manufacturer has carried out, the systems that achieve the highest energy savings are those that have been flushed first.

Can EndoTherm work with or without an inhibitor and cleaner?

EndoTherm compliments inhibitor products. This applies to systems already dosed with an inhibitor and systems where an inhibitor is introduced after EndoTherm has been installed. EndoTherm has some inhibitor properties itself and functions alongside inhibitors without issue.

Is EndoTherm dangerous?

EndoTherm is not dangerous to touch. It has the official classification of a “mild irritant” but carries no hazardous threat.

Can EndoTherm be used in an open vented system?

Yes, EndoTherm can be used in both closed and open wet based central heating systems. For open vented systems, we recommend you increase the dosage by 10% for optimal performance.

If you have any other questions. Please don’t hesitate in contacting us using enquiries@endoenterprises.com or call us on +44 (0)1925 747 101

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