Frequently Asked Questions

How many radiators do I need?

You can have as many or as few as you would like, but the common practice is to have radiators in the bedroom, living area, dining area, hall and bathroom.

Do you have units that can provide instantaneous hot water and heating?

Yes we do. We recommend that these units are only used in small/medium properties with 1 bathroom. This is because Immergas Combination Boilers can produce hot water flow rates of up to 22 litres per minute. For large multi bathroom homes we would suggest stored hot water.

Does the boiler have to be fitted inside?

No. We have both internal and external models. The internal boiler may also be fitted in a partially protected area. This is an area that is not affected by weathering. For example: A carport.

How do thermostatic radiators valves work?

Thermostatic radiators are valves fitted with an air sensor. It controls the flow of water into the radiator. The thermostatic sensor is oil filled and expands with heat pushing down on the pin inside the valve. When the desired air temperature is reached the valve closes and the radiator cools down. When heat is required the thermostatic head contacts and lets water flow through to heat the radiator.

How hot do the radiators get and is it safe for children?

It is safe for children in that there are no naked flames or electrics. However, as the radiator does heat to 75'C common sense needs to be exercised when very young children are present. Appropriate measures should be taken to prevent them being able to touch the radiator panel.

How much does it cost to install?

Hydroflow is only a distributor of the products and does not install. We can recommend a plumber to you. Plumbers charge different rates. An estimate of supply and install would be a small home $9,000.00, and medium home $12,000 and a large home $15,000.00.

How much does it cost to run a heating system?

This is probably the most important question.

In reality a number of variables will influence the running costs. They include:

How long do you intend heating your home? In the example we work on 6 hours per day.
How well insulated is your home?
How is the house constructed, window areas, ceiling heights etc.?
What is the external temperature?
What is the desired room temperature?
Does the whole house need to be heated or only selected rooms?


To completely heat a typical 3 to 4 bedroom house will require 10 x 10.5kw radiators.
Based on 6 hours heating per day the estimated heating cost* would be:

Gas $5.04/day

LPG $11.40-12.60/day

Diesel $10.70/day

*based on typical fuel costs, these may vary region to region.

What piping system is used?

Hydroflow recommends the use of John Guest Speedfit. It has been designed for heating systems and has an oxygen barrier within its construction. This is critical on heating systems as it stops oxygen ingress into the water.