Does a heat pump dry out your skin?
It can feel that way. Warming air lowers its relative humidity, and sitting in moving, warm air can leave skin feeling tight. But many New Zealand homes start out damp rather than dry, so a heat pump often brings humidity into a healthier range. Check with a cheap humidity meter before you buy a humidifier, and look after your skin with a moisturiser.
What a heat pump does to indoor air
Warm the same air, and its relative humidity falls. A BRANZ study of a 1980s Wellington house shows how big that can be: relative humidity in the main bedroom was over 70 per cent for 87 per cent of the time, and once the room was heated to 20 degrees, that fell to less than 1 per cent of the time.
That's good news for the house. BRANZ recommends a relative humidity of 40 to 60 per cent, because damp encourages mould and dust mites. So for many homes a heat pump improves the air, even if your skin notices the change.
Does it actually remove water?
Consumer NZ explains that a heat pump's dry mode works the way dew forms on the cold indoor coils in cooling mode. On heat mode, the drier feeling comes mostly from the temperature change. And a heat pump doesn't always leave a house dry: BRANZ found that 17 per cent of 134 New Zealand homes with heat pumps still had high humidity, and says heating and ventilation both matter.
Why your skin might still notice
- Moving air. DermNet lists direct heat from a fire or fan heater, and excessive air conditioning, among causes of dry skin. A heat pump blowing straight at you is in the same territory.
- How close you sit. BRANZ reports that heat pumps are now in more than 60 per cent of New Zealand homes, and a lot of us spend winter evenings right next to one.
- Other winter factors. Hot showers and cold wind add up. See dry skin in a New Zealand winter.
What to do about the room
- Measure first. A cheap digital humidity meter tells you what's going on. Aim for BRANZ's 40 to 60 per cent.
- Point the vanes away from you and away from your bed.
- Only use a humidifier if the air really is dry. The American Academy of Dermatology suggests one for dry skin, but in a damp house it can push you past the level that keeps mould and dust mites down. If you use one, clean it regularly.
- Ventilate anyway.
What to do about your skin
- Moisturise on damp skin after washing, and again through the day if you need to.
- Go a little richer in winter. DermNet says the drier the skin, the thicker the product should be.
- Try a hydrating layer under moisturiser. Hyaluronic acid works best sealed in.
- Keep showers warm and short. The AAD suggests five to ten minutes.
A mask for heat pump skin?
We wrote Hyaluronic Acid with this in mind. In the words of its page: "Air-con at work, the heat pump at home, a cold southerly on the way in." It gives you a cool, hydrated feel for the evening. It won't change your indoor air, and a daily moisturiser will do more over the winter than an occasional mask. Our page on dry, tight skin has more.
Questions
Should I use a humidifier with a heat pump?
Only if a meter shows your air is below about 40 per cent relative humidity. Many New Zealand homes run damp, and BRANZ recommends staying within 40 to 60 per cent.
What's a good indoor humidity in NZ?
BRANZ recommends a relative humidity of 40 to 60 per cent, which is a sensible target for your skin too.
This is general information, not medical advice. If you're worried about your skin, see your GP or a skin specialist.
Sources
- Research Now: Indoor air quality #1, BRANZ
- Is it worth using the dry mode on your heat pump?, Consumer NZ
- Dry skin, DermNet
- Kiwi homes are warmer than two decades ago, but we're still sleeping in the cold, BRANZ
- Dry skin: self-care, American Academy of Dermatology