"Dampchaser"

[Dell]

My cousin who is advising me on what to do to prevent dampness in my NZ house (besides buying a north-facing house) uses these 'damp chasers'. She suggests that when I'm back in the U.S. for a month or two and my NZ house is closed up, to leave one of these running in the bedroom.

http://www.dampchaser.co.nz/index.html

I recently stayed in a friend's guest house on the East Coast of the U.S. There was more mold in the house than I've ever seen in a NZ home - so it is not a problem restricted to NZ.

[JandM]

Not this same brand, but my parents used to have a gadget like this as the only heating in their downstairs loo, which was on the outside corner of the house. It certainly made a difference and took the chill off - at the neighbour's house, of the same design, the smallest room was freezing in comparison.

[Falcon_XR6]

Just buy a dehumidifier It's by far the best way to keep a house damp free and they are cheap enough to buy. We've run one since we moved in 5 years ago and we live 100yards from the sea and the house is totally damp free and the R/H is way down.
When we moved in the house felt very humid to me, so I bought a freestanding dehumidifier and it was pulling 2 gallons+ of water out of the atmosphere a day for over 2 months until all the moisture was removed from the walls, carpet etc. Visitors always ask if our house has central heating and that is only because it doesn't feel damp anymore.

Cheers
G

[Manks]

Just buy a dehumidifier It's by far the best way to keep a house damp free and they are cheap enough to buy. We've run one since we moved in 5 years ago and we live 100yards from the sea and the house is totally damp free and the R/H is way down.
When we moved in the house felt very humid to me, so I bought a freestanding dehumidifier and it was pulling 2 gallons+ of water out of the atmosphere a day for over 2 months until all the moisture was removed from the walls, carpet etc. Visitors always ask if our house has central heating and that is only because it doesn't feel damp anymore.

Cheers
G

If Dell's going to be away a couple of months though, who's going to empty it? There's one of those in our downstairs wardrobe. I've no idea how effective it is (except for the fact that we don't have any damp!). It's just switched on and doing its thing.

[Falcon_XR6]

You can get them with the necessary plumbing to run the outlet directly outside so you don't have to empty it and it works continually. Ours has the where-with-all to do this but I want to be able to see just how much moisture the device is extracting.

Cheers

G

[Dell]

If things work out with the house I've made an offer on, I might not need either as the house has an HRV system. It'd have a timer attached to it so that it would come on every day for an hour or two.

[Falcon_XR6]

These dampchasers just appear to be a heater and they don't actually get rid if damp, they just move it on to some where else.
The only way to stop this damp is to remove the water from the equation.
I even keep a nonelectrical, disposable dehumidifier (http://www.mitre10.co.nz/how_to_guid..._dehumidifier/) in my gun safe to remove any excess moisture from the inside as it is also a Fireproof safe with full carpeted interior and shelves and has an internal capacity of 315lit (11.3 Cu ft) so plenty of space for water to get trapped.

Cheers
G

[Wolfram]

Raising the air temperature reduces the ambient air's ability to hold moisture, plus warmer surfaces are less likely to have moisture condense on them. If you can't wont heat your house this is a reasonable attempt to at least keep clothes dry.

[Falcon_XR6]

As temp increases then relative humidity decreases (don't forget that this is not an absolute single value of the amount of water, it is dynamic and the figure varies with temp), there is no decrease in the water content of the air with temp unless you reach saturation point at lower temps i.e. the Dew Point has been reached. At higher temps more water vapor can be held in the air without it condensing out. R/H is the percentage of the maximum amount of water that the atmosphere can hold suspended, or in other terms, how close you are to forming condensation (if the Dew Point has been reached).

As an example, if the air can hold 1 part per million water vapor, and there is only ½ part per million water, you are at 50% humidity. if you warm the air so it can hold 2 parts per million, without adding any water then you are at 25% humidity... Note, the SAME amount of water is actually present. Conversely, if you introduce a cold glass of beer into the environment, and it cools the air immediately around the glass so it can only hold 1/4 part per million, the air immediately around the glass has 200% humidity, and the water condenses out of the air and beads up on the sides of the glass.

On your bathroom mirror, the opposite happens: as you take a hot bath or shower, the hot water vaporizes into the air, increasing the humidity, until the air cannot hold all the water and it condenses onto any slightly cooler surface tiled walls, glass mirror, window etc. If you continue to pump water vapor into the room, it will condense onto the walls and run down onto the floor.

A dehumidifier works by refrigerating a condensing surface, so that air drawn through the dehumidifier will exceed 100% humidity and water condenses out of the air onto the condensing surface.

So, with a temperature increase, relative humidity will decrease, unless more water vapor is introduced.
Increasing air temp does nothing to remove water from the atmosphere in a house, it just means that more water vapor can be taken into suspension in the air from, cooking, showers, the act of breathing our etc and all the items that can absorb water, paper, fabrics, wall boards, carpets etc just take in the extra moisture until they reach equilibrium with the air in the house.

A dehumidifier is the only way to get rid of water from the internal atmosphere of any enclosed space.

[MetalSoul]

If things work out with the house I've made an offer on, I might not need either as the house has an HRV system. It'd have a timer attached to it so that it would come on every day for an hour or two.

HRV is meant to be left on 24/7, I thought?