Low cost effective heating for bedrooms

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#1259948 16-Mar-2015 00:19

Aredwood:

The landlord probably installed an HRV, or a DVS, or one of the many clone systems. All they do is take air from the roof space and blow it into the rooms. Which will only fix a condensation problem that is caused by too much moisture generated inside the house and where there wasn't enough ventilation.

But when outside moisture levels are also high. Then such systems are useless. And in a brick house, Often the space between the framing and the bricks is open to both the roof space and the underfloor space. So an HRV style system ends up blowing damp underfloor air into the house. And if the house has a clay or concrete tile roof. often the tiles will also release alot of moisture into the roofspace air. And the HRV sales reps AFAIK get paid commissions for each system sold. So it is unlikely they will admit that their system won't be suitable for a particular house.

So although such systems can dehumidify in the right situations. They are definitely not true dehumidifiers.

In an ideal world, a balanced ventilation unit (with air-to-air heat recovery) and ducted heatpump :o)

Do you have a shower/bathroom close to the cold end of the house?

If the bathroom doesn't have an extraction fan, try and suggest one to your landlord. If you can remove excess moisture at its source it can make a big difference to nearby bedrooms. Especially with kids in the house always opening and closing bathroom doors.

My daughters end bedroom at her Mum's place used to get really damp windows. The bathroom door was always closed and window open. I put an extraction fan in anyway and the bedrooms stay way drier now. The heatpump is three rooms away and aims for the hallway from the living room.

edit: How I make the most of power savings in Winter... I unfortunately don't have a heatpump or fireplace. I have a 3KW scope permanently wired on thermostat at my flat (the landlord was to cheap and only had a 2KW plug-in fan heater). However during winter I run a 500W water distiller for 4 hours over night which keeps the chill off and gives me clean water for free (well that's how I look at it).

A mate was lucky to have a nightstore beside his baby's bedroom. He got the nightstore removed but put a panel heater in that still uses the night circuit for cheaper rates :o) About 13 cents a KW and only a 0.4KW/h heater.

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#1259955 16-Mar-2015 06:54

I suggest a 5 or 8 fin oil heater set to low in the hallway.
With the heat pump in the lounge, you will find that it only requires a little bit of heat at the other end to make it feel much more balanced.

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timmmay

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#1259965 16-Mar-2015 07:23

Niel: Before we had the aircon, in both our new built house and or previous 40 year old house, the best heating I've had was with cheap 5-fin electric heaters and placing a fan on top of them blowing down (was a cheap computer fan on a 12V power supply). Normally the thermostats in oil fin heaters don't work because the metal heats up and then the thermostat does not sense room temperature. With the fan however, the warm air is blown down and the area where the thermostat is does not heat up. Also the warm air is blown to the floor where it spreads through the room before it rises, instead of rising straight above the heater and collecting against the ceiling. The setup sounds stupid, but my wife was impressed in the living room she could feel the warmth at her feet with the heater 5m away. And do also get a dehumidifier with humidity sensor.

...You do get draft stoppers for ducting, but you might want to look at eBay as local prices are high. There is one model that is a sock inside a pipe that collapses when the fan is off, to stop the draft. All others are metal plates with a spring where you loose a lot of air flow when the fan has to fight the spring to open the flap. The sock system works well.

Niel, would you mind linking to the sock style draft stopper? I looked at them last year in NZ but as you said they're expensive and looked fragile.

How did you connect the 12V fan to a psu? Custom plug? I've done it in the past by cutting the plug off the fan and soldering a socket on.

raytaylor: I suggest a 5 or 8 fin oil heater set to low in the hallway.
With the heat pump in the lounge, you will find that it only requires a little bit of heat at the other end to make it feel much more balanced.

We put a smaller one in each room. Given heat goes straight up I'm not sure how much movement of heat between rooms there'd be. In our very old but well insulated house, with insulation all sides and cheap double glazing, a 1200W oil heater keeps our large bedroom plenty warm enough.

Niel

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#1259968 16-Mar-2015 07:31

timmmay:
Niel: Before we had the aircon, in both our new built house and or previous 40 year old house, the best heating I've had was with cheap 5-fin electric heaters and placing a fan on top of them blowing down (was a cheap computer fan on a 12V power supply). Normally the thermostats in oil fin heaters don't work because the metal heats up and then the thermostat does not sense room temperature. With the fan however, the warm air is blown down and the area where the thermostat is does not heat up. Also the warm air is blown to the floor where it spreads through the room before it rises, instead of rising straight above the heater and collecting against the ceiling. The setup sounds stupid, but my wife was impressed in the living room she could feel the warmth at her feet with the heater 5m away. And do also get a dehumidifier with humidity sensor.

...You do get draft stoppers for ducting, but you might want to look at eBay as local prices are high. There is one model that is a sock inside a pipe that collapses when the fan is off, to stop the draft. All others are metal plates with a spring where you loose a lot of air flow when the fan has to fight the spring to open the flap. The sock system works well.

Niel, would you mind linking to the sock style draft stopper? I looked at them last year in NZ but as you said they're expensive and looked fragile.

How did you connect the 12V fan to a psu? Custom plug? I've done it in the past by cutting the plug off the fan and soldering a socket on.

I'll see if I can find it again. Was not cheap, but cheaper than here due to economies of scale. I have not bought it yet, not needed in Summer so probably time I look at it again.

Yes, just cut the wires and solder to a wall power adapter (or old modem power supply).

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Niel

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#1259970 16-Mar-2015 07:35

kiwirock:
Niel: Regarding touching a hot heater, I was surprised with a fan on top of my electric oil filled fin heaters they were mostly cool to the touch. The fans would blow away the heat before the heater can heat up to where it could burn your skin.

Safer to put a fan behind it than on top. If the fan or fan power supply failed in the middle of the night... hmmm.

You don't set the thermostat to max, you set it to regulate the room temperature. In case the thermostat fails (very unlikely), the heater gets hot but not extremely. In case the fan fails, the thermostat is not set that high. The plastic used for fans will melt at a relatively high temperature, they are made for fitting to heat sinks that also gets hot. The big advantage of blowing air down is because the warm air then spreads along the floor where it reaches far, not horizontal/up. Try it.

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#1259972 16-Mar-2015 07:36

your house is not the same as OPs house, OPs house more like my old house. 60s. roughcast build. L shaped. 3 bedrm. barely 100m2. my ex house gets all day sun. i used to have 2 6kw heatpumps and 1 10kw one. 1 for lounge, takes the chill off. 1 for dining. takes the chill off. 1 for the square bit containing narrow corridor, toilet, bathroom, 3 bedrooms. corridor very warm. bedrooms, untouched. because the ceiling and floors were fully insulated i'm guessing all the heat escaped through the walls. all of it.

E3xtc

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#1259987 16-Mar-2015 08:20

When our baby arrived about 13 months back; he had to endure winter also, and his room was dropping below what we had considered a reasonable temp for a baby's room. So we looked around for cheap heating options, and ended up getting one of those panel heaters (importantly one with a thermostat on it), and just set it to a low temp (as earlier mentioned with the oil column heater)...I think 18 was where we had it too, and it worked a treat...kept the room from going stupid cold and also switched off when temp reached. Just my 2 cents.
But what others have mentioned about moisture levels really will make a massive difference. An older house we lived in, we got a dehumidifier and found we didn't really need a heater after that - it's amazing how much moisture is floating around...and you don't want to be heating all that water in the air :P

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#1259989 16-Mar-2015 08:26

i think your dehumidifier produced a small bit of heat and acted like a wall panel heater in the process of dehumidifying :D

alasta

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#1260005 16-Mar-2015 09:19

kiwirock: You need to regularly service a dehumidifier though. The coils will eventually get dusty and start growing mold or fungi from the lovely damp environment on the heat exchangers or drip tray. You don't want this blowing mold spores in to a nursery if it's tucked away over summer and pulled back out in winter.

My Mitsubishi Oasis has an automated internal cleaning function (button strangely labelled 'Mildew Guard Elite' as opposed to 'Mildew Guard' which performs an entirely different function) which the manufacturer recommends to run daily to prevent the problem that you describe. The only other maintenance is regular cleaning and replacement of the filter.

I know that dehumidifiers are often demonised on this forum as treating symptoms rather than the underlying problem, but honestly I wouldn't want to be without mine. Running the dehumidifier and heater together works a treat because the former works better in a warm environment and the latter works better in a dry environment. In mid winter here in Wellington I can head both my living room and adjacent bedroom with a 1.5kw oil column heater and the 250 watt dehumidifier together, whereas with a heater alone I suspect I'd need at least a 2kw unit.

timmmay

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#1260008 16-Mar-2015 09:22

I used to need a dehumidifier - I fixed the problem with plastic under the house and good extractors. Cheap double glazing (a rigid plastic sheet inside my main glass windows) reduced the condensation problems, but you couldn't do that as a renter. I always had a cheap DVS, which I've just changed to take air from outside rather than my dirty old roof cavity.

Fred99

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#1260009 16-Mar-2015 09:23

Cost (capital) of a second heatpump would be about $5/week over 10 years. Presumably the LL would want to recover this cost in increased rent.
For a bedroom, assuming approx 10 hours use overnight, thermostat controlled, average say 1kw output, used 6 months of the year, with fixed rates (not night rate), then there's little if any difference between added energy cost of a conventional heater and the total cost of a heat pump. In a cold frosty part of the country, the efficiency loss of the heatpump possibly tilts things even more in favour of the conventional heater, as would use of day/night rate if that suits the OP's lifestyle/energy use pattern. Even if the sums don't add up perfectly, the cost difference either way is probably trivial. Heating a living area (or entire house) where you might want/need 4-10kw output, then it's a different story.
An oil column heater would be the way to go IMO. I wish the manufacturers would substitute mechanical relays with solid state relays in these heaters, as they are silent in operation and much more reliable (though there'd still be the normal noises an oil column heater makes).
Other things to look at are drapes in the bedroom - which presumably isn't double-glazed - heavy floor to ceiling (or pelmet if fitted) "thermal" drapes can make a big difference and are relatively inexpensive "pre-made". If it's an older brick house, with no external wall insulation, and uses architraves around window joinery (ie as opposed to rebates where the gib slots in to the window frame), then check for drafts around the windows, small gaps can be sealed up with "no more gaps" etc)

Mumx5

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#1260058 16-Mar-2015 10:15

Hi everyone

Thank you for your responses.

I have spoken to the Landlord several times with the request to look at heating down that end of the house, however the landlord in the last month has just spend thousands of dollars on redecorating the entire house, installing new carpets and lino, and completely renovating the bathroom and has declared enough has been spent. I have even tried the argument installing a second heatpump or HRV or similar would hopefully reduce the condensation and therefore protect the windowsills and walls from the mould etc however this fell on deaf ears.

Our bathroom and toilet (2 separate rooms) are the same end of the house as the bedrooms, in fact located between them (2 bedrooms one end, bathroom, toilet then 3rd bedroom. I keep the doors closed to the toilet and bathroom to prevent heat loss.

I obviously don't want to install a permanent system as this is a rental property which is very reasonably priced (for Christchurch!) and is now in as new condition.

I am willing to pay out for a portable system, but obviously wanting to get it right and something that is "affordable" not just the initial outlay but obviously I am not going to be wanting outrageous monthly bills over winter, especially as during this coming winter will be the time where income is reduced.

It also needs to be child safe, as although my older children are all primary and high school age, I am going back to the start with this little one so safety from little fingers is paramount.

The size of the area needing heating is the issue, although the older childrens rooms just need the chill taken off them plus being dried out as they get very damp in winter, either I need to maintain a constant temperature for that entire end of the house at night (during the day I can have baby at the heated end of the house) or somehow heat babies room better.

What I am looking at is the following:
26L dehumidifier located in the hallway - big enough to remove the condensation from the three affected bedrooms.
425w panel ecoheat panel heaters, one in each bedroom.

Will the dehumidifier be quiet enough to run at night, utilizing the "heat" output to assist in warming that end of the house?
Will the dehumidifier work well enough that the ecoheat panel heaters would then produce enough heat to keep the bedrooms at an acceptable level (not talking about t-shirt level, just acceptable levels for children and babies).
Will this be an affordable option for winter?

I did look at a convector heater with the fan up the top located in the hallway, quite affordable to purchase however potentially costly to run overnight, with a thermostat (possibly heatermate) to ensure temperature stays just where it needs to be and we don't overheat. However I would still have the overnight condensation buildup to contend with.

Thanks for your input so far. Anyones thoughts on whether these systems I am considering will work are welcome, but a secondary heatpump, hrv system etc is ruled out by the landlord.

Batman

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#1260059 16-Mar-2015 10:17

i would put one dehumidifier in each room you want to heat. but not sure ...

timmmay

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#1260063 16-Mar-2015 10:25

I'd use oil heaters, they're easier to move. Opening windows can also dehumidify, though it loses heat.

A dehumidifier will reduce heating costs, but heating is expensive. The heat pump you have is the cheapest heating, what I do sometimes is put a big pedastool fan in a heated area pointed towards an unheated area - that works quite well.

This heat recover ventilator could be pretty effective, installed in a window, instead of a dehumidifier. More info here. No idea about costs, you could ask them - if you do please post here. You may have to replace a sheet of glass when you move out, if you install it in a window.

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#1260065 16-Mar-2015 10:26

when i bought my first house we slept in the lounge in winter! (heatpump)

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