For a basic project in zip code system, the cost to Install a Hydronic Heating System starts at $, $, per system. Actual costs will depend on job size, conditions, size options..Cost to Power Flush Central Heating System. Welcome to Plumber’s Rates and this guide to the costs you can expect to pay a plumber or heating engineer to power flush your heating system..*Disclaimer Actual costs will vary depending on weather conditions and usage. This information is intended for comparison purposes only. This calculator should not be used to determine the size of a new HVAC unit, it is intended for cost comparison purposes only..Why Choose Central Heating New Zealand? Since , we’ve am.ed a wealth of expertise about central heating products, system design and installations, with a focus on what works best for New Zealanders and our homes..