Browse Forums Heating, Cooling & Insulation 1 Jun 21, 2016 2:20 pm Hi guys After lots of research, I am still a bit confused about the different types of systems out there and what would work best for the double storey home we are planning to build (in Melbourne). In our current single storey home we built almost 10 years ago we have ducted gas heating with evap cooling add on (different vents for both). We have found it to work pretty efficiently, though I should point out that our house has lots of tiles and is always on the cooler side. The evap even works well at night with all the doors and windows shut, although we mostly just run the fan and keep the cooler off and that's usually enough. The only down side is that we don't have any zoning, so it's a bit inefficient heating and cooling the whole house when at night we only need it in the master bedroom. So I am thinking of a similar system again with zones for the new house, though not sure whether the extra storey would make a big difference. The master bedroom will be located downstairs, so I don't foresee heating and cooling the second storey much unless we have guests staying over. I hear lots of people pushing refrigerated over evap cooling (which I understand is the same as reverse cycle - correct me if I am wrong). But it seems refrigerated is more expensive to install and run, and given we don't have that many humid days in Melbourne, I wonder how worthwhile it really is for our climate. BTW I am not really a fan of air-con in general and it's a constant battle with hubby to keep the cooler off in summer! So naturally I am more focused on the heating side of things. Definite must have for the new house is a heating vent in the ensuite. No more stepping out of a hot shower into the cold! Anyway, any suggestions about how we can efficiently and effectively heat and cool our new home would be much appreciated, including recommendations for particular systems/brands. I'd also be keen for some feedback on how double glazing/insulation would work into the mix. Thanks Dani Re: Best heating & cooling system for a double storey home 2Jun 21, 2016 5:33 pm Yes refrigerated and reverse cycle are the same thing unless you are talking about a cooling only unit which by definition is not reverse cycle. Anyway I've never heard of a refrigerated cooling unit that was more efficient than Evap no matter how large the space being cooked so I wouldn't let the fact that you are cooling your whole house vs a zoned system to cloud your thinking. If your climate is ok for Evap I would do that for cooling and ducted gas with zoning for heat. The only thing you have to calculate is do the separate units themselves cost more than it would cost you to run a single reverse cycle system and for how long. Lots of these energy saving initiatives seem like they will save you but it takes 15 years to realise at which time most of these appliances are at the end of their life and need replacement. Bottom line do the real math to get your answer. Either that or go with whatever is the most convenient option for you:) Sent from an iPhone please excuse the ridiculous spell correcting software. My forum thread is at viewtopic.php?t=74944 Re: Best heating & cooling system for a double storey home 3Jun 22, 2016 12:24 pm In going to double storey, the main difference is that for ducted heating and cooling systems you need to take upper floor space to run ducts down from the roof. This takes up building area, which is equivalent to costing money. An evaporative cooling plus gas heating system would require large ducts for the cooling, plus the ducts for the heating as well, so somewhat more space than a refrigerated system would require. In many areas (perhaps not Melbourne), heating via reverse-cycle air-conditioning is cheaper than heating by gas, but evaporative cooling would generally be cheaper than ducted refrigerated air-conditioning. You can get much better efficiency by looking at the zoning. If there are a lot of time when you're just using one or two rooms, then you need to think about how the system will work. Most whole-of house systems don't scale down well enough to just a single room. In refrigerated systems Actron is about the only company that tries to do this. When doing zoning, with recirculated system (ducted refrigerated, and ducted gas heating) you also need to be aware of the return-air path. With whole-of-house systems, there's typically one return-air vent, which all of the air pumped out of the vents eventually returns to. Thus the path of air from the vents that are open through to the return air is also conditioned. For many houses this means that even if you can turn off most zones, the main open living spaces are heated/cooled to some extent, as the return air vents are typically close to these. This is an area where individual split-system air-conditioners can help. They are more efficient than ducted systems, and have more flexibility. as you can efficiently cool or heat just the small area that they are in. Typically the most efficient way of heating or cooling just a master bedroom would be a split system A/C in that room. The downside of a split systems is the internal aesthetics, and that you need an outdoor unit for each one. For this usage pattern, make sure that all the walls of the room are insulated. This is good practice anyhow, as it reduces sound transmission. Depending on the size of the house, it may make sense to have a whole-of-house ducted system of some sort, as well as one or more individual split system A/C units. This can give the possibility to condition large areas, but also have an efficient means of just heating/cooling the smaller areas in use. Given that you don't spend very much time in the bathroom, the most energy-efficient way of heating the ensuite may be to use heat-lamps, just to heat you up while you're in there. Regardless of what you use, more insulation, and double glazing will help with winter heating and condensation issues. Here in Adelaide, with decent insulation, you don't really need any heating at all, but being colder in Melbourne, there may still be some need. Re: Best heating & cooling system for a double storey home 4Jun 22, 2016 10:49 pm TheBigHouse Yes refrigerated and reverse cycle are the same thing unless you are talking about a cooling only unit which by definition is not reverse cycle. Anyway I've never heard of a refrigerated cooling unit that was more efficient than Evap no matter how large the space being cooked so I wouldn't let the fact that you are cooling your whole house vs a zoned system to cloud your thinking. If your climate is ok for Evap I would do that for cooling and ducted gas with zoning for heat. The only thing you have to calculate is do the separate units themselves cost more than it would cost you to run a single reverse cycle system and for how long. Lots of these energy saving initiatives seem like they will save you but it takes 15 years to realise at which time most of these appliances are at the end of their life and need replacement. Bottom line do the real math to get your answer. Either that or go with whatever is the most convenient option for you:) Sent from an iPhone please excuse the ridiculous spell correcting software. My forum thread is at viewtopic.php?t=74944 Thanks for the response BigHouse and the clarification. My gut is telling me to stick with ducted gas heating and Evap cooling. Just not sure whether to go with one unit as you pointed out or two separate like we have now. If it's the one unit, I am assuming it would have to be refrigerated cooling and the whole unit run on electricity. I would also assume you would only have one type of vent which might be more efficient than separate vents and loss of heat/cool through the other vent when not is use. Downside is if it breaks down, both the heating and cooling are affected! If they are separate units I.e. gas ducted and Evap, can you zone both? Re: Best heating & cooling system for a double storey home 5Jun 22, 2016 11:03 pm oneJohn In going to double storey, the main difference is that for ducted heating and cooling systems you need to take upper floor space to run ducts down from the roof. This takes up building area, which is equivalent to costing money. An evaporative cooling plus gas heating system would require large ducts for the cooling, plus the ducts for the heating as well, so somewhat more space than a refrigerated system would require. In many areas (perhaps not Melbourne), heating via reverse-cycle air-conditioning is cheaper than heating by gas, but evaporative cooling would generally be cheaper than ducted refrigerated air-conditioning. You can get much better efficiency by looking at the zoning. If there are a lot of time when you're just using one or two rooms, then you need to think about how the system will work. Most whole-of house systems don't scale down well enough to just a single room. In refrigerated systems Actron is about the only company that tries to do this. When doing zoning, with recirculated system (ducted refrigerated, and ducted gas heating) you also need to be aware of the return-air path. With whole-of-house systems, there's typically one return-air vent, which all of the air pumped out of the vents eventually returns to. Thus the path of air from the vents that are open through to the return air is also conditioned. For many houses this means that even if you can turn off most zones, the main open living spaces are heated/cooled to some extent, as the return air vents are typically close to these. This is an area where individual split-system air-conditioners can help. They are more efficient than ducted systems, and have more flexibility. as you can efficiently cool or heat just the small area that they are in. Typically the most efficient way of heating or cooling just a master bedroom would be a split system A/C in that room. The downside of a split systems is the internal aesthetics, and that you need an outdoor unit for each one. For this usage pattern, make sure that all the walls of the room are insulated. This is good practice anyhow, as it reduces sound transmission. Depending on the size of the house, it may make sense to have a whole-of-house ducted system of some sort, as well as one or more individual split system A/C units. This can give the possibility to condition large areas, but also have an efficient means of just heating/cooling the smaller areas in use. Given that you don't spend very much time in the bathroom, the most energy-efficient way of heating the ensuite may be to use heat-lamps, just to heat you up while you're in there. Regardless of what you use, more insulation, and double glazing will help with winter heating and condensation issues. Here in Adelaide, with decent insulation, you don't really need any heating at all, but being colder in Melbourne, there may still be some need. Wow thanks for the detailed response oneJohn! Really appreciate the specific advice on double storeys and insulation. So much to consider and get my head around. I agree split systems certainly have their advantages, though from an aesthetic point of view, I'm not a big fan. And I'd still want to heat and cool at least all of the downstairs during the day to avoid going from the hot to cold room phenomenon and vice versa. Perhaps an alternative is ducted downstairs only and some split systems upstairs, or is this not really an efficient option? As for heat lamps in the bathroom, have those at the moment and they don't do enough IMO and we have quite a small space at the moment. The ensuite in the new home will be much bigger and opens directly into the WIR (no door) so feel we need something to heat both areas. Re: Best heating & cooling system for a double storey home 6Jun 23, 2016 10:15 am One important thing to remember in a double storey home is that you need to be able to close off your stairwell, otherwise you'll find the running costs will blowout. Heating downstairs will take a long time because the warmth rises, and rises straight up through your open stairwell. Likewise cooling the house, downstairs will cool easier than upstairs for the same reason, heat rises. Upstairs will take a lot to cool down, because the cool will fall to the lowest part, i.e. the stairwell again. Of course closing off your stairwell isn't always going to be a viable option many if you've chosen to have the open step look for the stair case. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Best heating & cooling system for a double storey home 7Jun 23, 2016 8:39 pm Circulation is a key for Evap systems so to the points above around two stories you really need to be aware of pathways for return air ETC. Evap systems don't have a return path as such so that's not really a concern just as it wouldn't be for ducted heating on its own. So, I say go with what you are used to and comfortable with. Personally I hate the humidity of Sydney and need to be cool all the time so I need to have refrigerated air con as it serves both removal of moisture and cooling. I remember someone in the industry once told me there is no such thing as cold, only absence of heat:) Sent from an iPhone please excuse the ridiculous spell correcting software. My forum thread is at viewtopic.php?t=74944 Re: Best heating & cooling system for a double storey home 8Jun 24, 2016 10:13 pm bpratt One important thing to remember in a double storey home is that you need to be able to close off your stairwell, otherwise you'll find the running costs will blowout. Heating downstairs will take a long time because the warmth rises, and rises straight up through your open stairwell. Likewise cooling the house, downstairs will cool easier than upstairs for the same reason, heat rises. Upstairs will take a lot to cool down, because the cool will fall to the lowest part, i.e. the stairwell again. Of course closing off your stairwell isn't always going to be a viable option many if you've chosen to have the open step look for the stair case. Good point except we have a void above the entrance. Will look great but not so energy efficient...! Re: Best heating & cooling system for a double storey home 9Jun 24, 2016 10:15 pm TheBigHouse Circulation is a key for Evap systems so to the points above around two stories you really need to be aware of pathways for return air ETC. Evap systems don't have a return path as such so that's not really a concern just as it wouldn't be for ducted heating on its own. So, I say go with what you are used to and comfortable with. Personally I hate the humidity of Sydney and need to be cool all the time so I need to have refrigerated air con as it serves both removal of moisture and cooling. I remember someone in the industry once told me there is no such thing as cold, only absence of heat:) Sent from an iPhone please excuse the ridiculous spell correcting software. My forum thread is at viewtopic.php?t=74944 Thanks BigHouse. 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