Hello,
First post on the board - so forgive any protocol issues. After 12 months of planning and permits we are about to sign our building contract for a 3 level townhouse in inner Melbourne. Our only open issue is around the heating and cooling.
We have had lots of advice but are still very confused. Our ideal would be hydronic heating throughout - but also need a cooling option as we all struggle in the heat. This would see us with a $35k bill. I am of course concerned on the cost, and think there must be a better option.
Our only other advice is to install a inverter multi head split - eg Daikin unit with 7 heads. Would be half the cost to install.
My questions are -
I have heard that hydronic can be slow top warm up if not left on all the time?
Is the heat from the inverters warm and are they quick to warm up rooms?
Looking for any pro and con for these options?
Thanks
We have found inverter systems good and fairly quick, yes the air feels warm.
With hydronic systems systems it can be a bit slower with radiators and slower still with underfloor heaters.
If cooling is important I would go for the inverter system
Hi,
I'm an installer of both hydronic heating and reverse cycle air conditioning systems- we come across your dilemma frequently with clients- a quick answer isn't that easy. If you're planning to stay in the house for more than 4-5 years, the savings you'll make on the running costs of a hydronic heating system will often go close to paying off the installation difference. Electricity, even with inverter technology, is a fairly inefficient and increasingly expensive fuel to use for heating- I'd suggest doing some basic cost calculations for running the both systems before making your final choice.
A hydronic system shouldn't take much more than 20 minutes to reach temperature- with a programmed thermostat, the system can be programmed to come on 20 minutes before heating is required, negating any 'heat lag' issues.
Air-conditioners are usually quicker, and programmed controls can also be used to eliminate any unwanted heat-up lag. Melbourne's climate doesn't require full time heating- that said, it can actually be more energy/cost efficient to run a back-ground heating program on your system that keeps your house from dropping below 12-14 degrees in winter. The hydronic boilers available in Australia use very little energy to do this- particularly condensing boilers (more expensive to purchase.....). Trying to achieve the same with reverse cycle air-con is not practical or cost effective.
A compromise that we commonly find works is to instal a hydronic heating system in the main downstairs levels (living/entertainment areas?), for around half the price of a full hydronic installation. Then use a reverse cycle air-conditioning system to heat and, more importantly, cool upper levels. You will get a fair bit of natural rise (or heat loss) from the hydronic system to the upper levels, often negating the need to use any heating. In summer, cooling upstairs will often mean very little, or no cooling is required on the lower levels. Depending on your house layout and orientation, this may be a suitable and cost effective solution...?
Another important issue, often under appreciated, is the comfort level provided by the respective systems. Heating air, then blowing it around a room is not a particularly comfortable way to heat a room. Air is an great insulator, not a good medium for heat transfer. Radiant heat is more subtle, dust and noise free- and requires comparatively lower room temperature to provide comfort. Only the client (...you) can put a dollar figure on the value of it.
good luck!
Hi Loosh, just regarding your comments regarding hydronic being cheaper to run that gas how do you know this. From my understanding it is about the same or slightly more than gas heating. Also inverter is the most effecient system but year it still cost more to run due to electricity prices. Inverters are over 300% effecient.
Thanks for the advice loosh....we are going with Hydronic for the heating and split's on the upper level - advice is the ground floor should not heat that much.
now to find the right installer for the hydronic
Hi Rain,
hope the advice helped a little- we find that combination works really well with the right house layout.
I don't want to hijack the forum trawling for work, but if you end up in our shop, hopefully we can help you out!
Regardless of who you end up with, try not to focus only on how many radiators they're putting in, ask how much heat hey are providing with the system (usually measured/shown in kW) . We're noticing a trend of contractors quoting a reasonable number of hydronic radiators, but only half the size of what is required. That said, there are plenty of good heating contractors around in Melbourne, your architect, builder. etc should be able to put you in touch with one.
Good luck with the build!