Our 7.2 kW (heating) Panasonic reverse cycle split system heat pump made our living room feel stuffy, and left us with cold feet, despite its installed cost of $2,790.
We didn’t have that problem with our previous 4 kW Kelvinator window-rattler, which had provided most of our heating with reasonable economy, though in mid-winter it needed help from our gas heater.
With the new split system, ankle-level temperatures measured about four degrees lower than shoulder-level temperatures.
To get warm feet, we could have raised the thermostat by several degrees, at the expense of increasing our heating costs by about a quarter.
The manufacturer confirmed that the indoor unit has been installed two metres above floor level, as per the manufacturer’s instructions.
Those instructions were obviously developed for hot climates, where cool air from the unit, being denser than the ambient air in the room, would fall towards the floor.
In Canberra’s climate, the warm air from the unit stays near the ceiling until it starts to cool and is pushed downwards by fresher, warmer air.
The indoor unit’s fan is powerful enough to get warm air near floor level within two metres of the unit. It is not powerful enough to get warm air near floor level where we normally sit, four metres from the unit.
A more powerful fan might have solved the problem.
A simple solution would be for Panasonic to amend its installation instructions, to allow the indoor unit to be installed closer to the floor in cold climates, so that the hot air would come out near floor level and then rise through the room.
We eventually fixed the problem by replacing one of our living room lights with a combination fan/light, at an additional cost of $600, to blow hot air from the ceiling down towards the floor. We get good results by blowing air downwards on speed 2 (of 6). We can also avoid the cooling effect of being in the direct line of the air from the fan, by blowing air upwards, at a higher speed, to mix the high warm air and the low cool air.
It is not just the installation of split system air conditioners that has a problem with heat for winter. I have a large ducted system in my two story home. I found we had a problem with getting hot air to floor level and so I suggested to the air con people that the duct in our family room be moved lower. This was apparently far too radical an idea for today’s air con people so they installed it on a side wall about 2 meters from the ground. This did not solve the problem, so I, completely untrained in air conditioning installation, studied the problem, looked at our house plans, worked out where studs, electrical cables etc were, and installed the duct myself at floor level, added the extra flexible ducting to reach, patched the wall and had the ducting boxed and gyprocked where necessary. All with absolutely NO help from any air conditioning company. The result totally solved the problem in that part of our house, eliminated the cold spots in winter and still worked perfectly for summer because the cold air in summer is drawn back up to the return vents upstairs and therefore does not “pool” near the floor. I have a similar problem in another part of the house and after discussion with several air conditioning companies and finding the same incredible resistance to try anything new, I realise I am going to have to solve this problem myself again by putting at vent at floor level.
I had a similar situation when I was choosing an air conditioning company at the beginning. I wanted a fresh air input that would allow me to draw fresh air from outside when I need to refresh the air in the house, particularly if there were a lot of guests and the CO2 level had risen high (yes, I have a meter that measures that), or for use in summer, when after a hot day the outside night air was all that was needed to cool the house for sleeping. I found only one company that would even consider adding this feature for me and it is brilliant - I use it regularly simply at the choice of a zone on the control pad. Amazingly numerous air con companies told me it couldn’t be done or they didn’t know how or they weren’t interested!
I don’t know if air conditioning companies overseas are as stupid as the ones in Australia are but I find it incredible that in this supposedly advanced technological country air conditioning firms are so primitive.
Ask them to put some vents near the floor to distribute hot air in winter and they look at you as though you are mad! Well, let me tell you it CAN BE DONE AND IT DOES WORK!!
It’s not novel or new. Low energy ‘eco’ design homes are often designed with air exchange ventilation. They can incorporate air quality monitoring, filtration, heating and cooling. The everyday residential ducted air conditioning installers tend not to look outside the box.
Please excuse a brief diversion. Commercial systems for large buildings need to be energy efficient and are typically closed environments. They only heat or cool the air they draw in sufficiently to meet needs. The ventilation systems distribute through ducting. The specialist HVAC designers are also familiar with energy recovery from the waste air stream (heating or cooling) to reduce energy consumption.
For residential inspiration there are some better informed businesses. Several examples, for those looking to research further.
- ‘https://shop.freshventilation.com.au/products/dvs-ec-premium-connect-home-ventilation-system
- ‘https://zenithventilation.com.au/
Why any local ducted system supplier might only offer a one design fits all solution? Possibly most are owned by tradies who only know what is in the installation manual provided by their brand supplier. Is it all they know, or is it just a convenient sell? Many are selling retro fits to existing properties or add ons to new builds without design forethought. The poor outcomes seem self assured.
P.S.
Keeping feet warm can be achieved simply with a nice pair of indoor slippers or … bare feet optional.
@LeonArundell I’ve recently bought some “Oodie” brand hoodies which are huge (must be if they fit me) and which are the warmest items of clothing I have. I’ve only turned on heating when I get sick of the bulk of the Oodie. Oodie has recently brought out a range of sherpa fleece lined socks. I’d almost guarantee that within minutes of donning them, your feet would be warm as toast.
Regarding heat near floor level as @rjstevens added is not a difficult goal to achieve with a ducted system. With other systems, while there are numerous ways to keep one’s feet warm (socks, slippers, whatever) that is not everyone’s fancy and unfortunately suggests the goal might be a bit precious? - which it is not for some people.
The use of words for describing warmth near floor level will deliver differing sensory expectations to differing readers, each valid for that reader. A split installed at the typical 2m height might not blow air comfortably or consistently as it cycles.
I empathise with the OP but the only metric I can imagine that could be empirically tested would be related to blower capacity and the effectiveness of the louvres, heating/cooling capacity being equal among the compared units.
No doubt your Oodies cost a lot less than $3,000.
I empirically tested the air temperature at shoulder and ankle heights. The temperature at ankle height was four degrees lower than the temperature at shoulder height. A three degree difference is enough to make the room feel stuffy.
Not unexpected. Our mum often complained huddled in the chair that the RC was not keeping her warm, compared to squatting next to a radiant type heater. The remainder of the house though was like an ice box and the power bill high due to the poor efficiency of the old way.
The ubiquitous RC split systems are typically installed towards the ceiling as they are used predominantly for cooling. In colder climates indoor units that are floor or in wall mounted are also common, and located to better provide for winter warming.
We have an elevated home with timber floors open beneath (no under floor insulation). In winter we set the RC vanes to point vertically down and the side louvres to swing. In our larger space running one of the ceiling fans on low fine tunes the outcome at minimal extra power use.
We lived many summers in the hot damp tropical north of QLD. Using the ceiling fans in low made a significant positive difference to comfort while using the air cons. It’s often quoted there is a penalty of 10% more power required for every 1C cooler. Doing the same in winter comes naturally, if not intuitively. Supposedly best with the fan rotation reversed.
P.S.
Underfloor insulation is on the shopping list, providing concerns of condensation risks/damage and BAL requirements are resolved.
Companies like Vulcan created ‘upside down’ heaters in the 1970s, when the realised that heaters provide better comfort if their fans emit warm air near floor level (rather than assisting natural convection by blowing warm air out the top of the heater).
Despite that, I have never seen the indoor unit of a split system air-conditioner mounted close to floor level.
I recommend underfloor insulation if you live in a cold climate. In winter, the surface an insulated internal floor or wall is warmer than it would be it was not insulated. That makes condensation less likely to occur. Our wall mould disappeared after we insulated our walls.
One example.
It’s a good point that the discussion should clarify the type of home construction and climate/environment that it is set in. Solutions vary.
The “Wera” floor console seems to have been available in Australia only since February 2021.
We need more manufacturers to follow Mitsubishi’s lead, in providing indoor units that are suited to cold climates.
Choice has reviewed 13 different models of floor mount. They are not a new thing in the world of split system AC’s. Until more recently winter heating in the colder parts of Australia has been better delivered by other solutions. It’s easy to see why the major manufacturers may have promoted high wall split systems, as the far greater demand has been for summer cooling. They do as good a job in winter when combined with adequate room air circulation, IMO.
If your mum is still feeling the cold, I would be getting her some nice thick throw blankets to help her keep warm or there are electric heated throw blankets which will keep her as warm as toast.
In regards to the problem of having cold feet due to your heating/cooling system not doing the job of circulating the heated air evenly, there are simple measures that can be considered. Try using extra thick wooly socks and heavier thicker footwear. You could consider purchasing an electric foot warmer, which should fix the problem for the coldest feet.
Blankets and foot warmers are excellent and inexpensive ways to keep warm. They would not be necessary if heaters, that can cost thousands of dollars, did their job properly.
A very energy efficient solution. It’s ideally suited to the older style Aussie abode. One which can be difficult and expensive to update to the very best in insulation. The costs of doing so are also significant for a second best outcome compared to building from scratch.
The most practical (for the not so nibble or flexible) are built into a raised platform the height of a dining chair for ease of access. Speaking with the experience of several less nibble Aussies including one with a double knee reconstruction. In a room warmed to only moderate temperature, but well above the outside -10C and snow it’s a great way to toast the tooties, and any other bits that feel the cold.
Also a great way to make the most of the home budget. There is the possibility of placing your table over a large rock heated during the day by a solar powered heat pump. EG a 1 metre cube of solid granite will release approx 0.5 kWh of thermal energy for every degree centigrade of temperature lost. Heat to a modest 50C and treat it as a 1kW heater under the table. Toastie! 5 hrs after the sun has gone down it will have fallen to a more body warm 40C. Alternately when not powered by the sun a modern efficient heat pump can provide a similar output for less than 50 cents, and much less if off peak.
Does Choice really need to score individual products on their floor warming? Choice has addressed the benefits, pros and cons of the different technologies and systems including the costs. Some will see warm feet as the reason to purchase a particular product. I’d rate a Kotatsu 10/10 for foot warming regardless of brand or model. I’d also rate under floor heating a great option for homes designed and built for it. If cold feet is a concern and warm socks and boots don’t do it for one, the decision is about which method of heating is most appropriate. These are better options for warm feet with no need to rate a high wall mounted RC AC on foot warming. Doing so risks introducing a bias to the results.
The purpose of a heater is to make people comfortable.
Choice scores individual heaters. Some split system heat pumps distribute their heat well around a room. Others don’t. The ones that produce poor heat distribution should not score as highly as those that do.
Although a solar powered heat pump could provide excellent heating quality at low running cost, its initial cost would be very high.
If a table (or better still, a concrete floor) is heated using electric resistance heating, it will provide excellent heat quality, but will cost several times as much to run, for a given amount of heat, as a heat pump.
The two concepts can be combined, you can have heat-pump pipes in your floor. It is not cheap, usually reserved for high value installations in cold climates. Of course that will not cool you on hot day where a reverse-cycle aircon will do both.
Even the best floor level heating beyond in-floor slab will depend on the structure. A heating unit can only do so much from floor to head height if the building/room is not environmentally ‘tight’. Dependencies include ceiling, wall, and underfloor insulation, brick veneer, double brick, or wood construction, metal or tile roofing, and whether the house is on a slab or stumps. All those aspects come together but each individually will be part of the overall ‘equation’ for heating (as well as cooling).
Some easier treatments for ‘cold feet’ caused by the dwelling and heating system’s characteristics include carpet, area rugs, and for homes on stumps, underfloor insulation (not always cheap depending on area to be insulated).
If there were a test as suggested, would it be applicable in a general case or would it be more variable from house to house depending on the issues I mentioned, and while possibly being an interesting data point would it regularly result in the expected outcome? Or will any particular building out weigh the end result - eg poor insulation will result in a more variable temperature across a room from end to end as well as floor to ceiling, etc?
