It’s the middle of winter in Auckland. Your home feels cold and damp, and despite running your oil heaters and dragging out Gran’s old dehumidifier, nothing seems to help.
So what do you invest in next? A modern energy-efficient heat pump for Auckland winters to warm things up? Or a whole-home ventilation solution for damp Auckland houses like HRV, DVS or SmartVent to dry things out?
Before you spend a dollar, you need to identify your home’s biggest problem:
Step 1: Identify the Issue
- Is your home damp?
- Signs include excessive morning condensation on windows.
- Damp air promotes mould, rot, and is harder to heat.
- Is your home cold?
- If you’re in five layers and can see your breath indoors, it’s time to rethink your heating strategy.
- Plug-in heaters max out at 2400 watts and are often insufficient for older or poorly insulated homes.
- Is your home both cold and damp?
- Many Auckland homes suffer from both, making the indoor environment uncomfortable and unhealthy.
Heat Pumps / Air Conditioners
- Primary Benefit: Strong heating power
- Secondary Benefit: Minor dehumidification in some modes
If your main concern is warmth, a heat pump is the way to go. We’ve seen how the right setup can completely change the feel of a space.
Heat pumps are highly efficient compared to plug-in heaters:
- 2000W electricity input into a standard heater = 2000W heat output
- 2000W electricity input into a heat pump = 6000-8000W heat output
They circulate room air through an internal unit, heating it and returning it back into the space. However:
- Heat pumps do not add fresh air to your home.
- Warmer air can carry more moisture, so the air may feel drier, but the actual moisture content stays the same.
What about the "Dry” or “Dehumidify” Mode?
How this function works:
- The heat pump goes into cooling mode
- Air passes over cold coils within the internal unit
- Moisture condenses on coils, drips to a collection tray and is drained away to the exterior of the home
Downsides
- This process consumes a lot of energy.
- It works by cooling the room, not ideal in winter.
Summary:
If your home is freezing, a heat pump is your best choice for reliable,cost-effective heating.
Is There a Difference Between a Heat Pump and Air Conditioner?
No, they are two names for the same thing:
- "Heat pump": Often used in NZ, may imply heating-only
- "Air conditioner": More accurate, as they heat, cool, and dehumidify
Ventilation Systems (HRV, DVS, SmartVent)
- Primary Benefit: Strong dehumidification
- Secondary Benefit: Minor heating in specific conditions
If your main issue is moisture and condensation, then a ventilation system is your best bet
These systems push warm, dry air from the ceiling cavity into your home through filters, pushing out stale, moist air.
This:
- Reduces condensation
- Removes damp air
- Improves indoor air quality
Temperature Impact
- On sunny afternoons: the ceiling air may be warmer, slightly heating your home
- On cold mornings: ceiling air may be cooler, slightly lowering your home’s temperature
But remember: a dry home is easier to heat than a damp one, so even if the air is cooler, your heating system will perform better.
Summary: If dampness, mould/mildew and crying windows are your main issues, a ventilation system will drastically improve air quality and dryness.
HRV vs DVS vs SmartVent: What’s the Difference?
Essentially, all of these systems do the same thing.
- Draw warm air from the ceiling cavity
- Filter it
- Push it into the home, forcing stale air out
Differences lie in:
- Product quality
- Filter & Sensor technology
- Installation
- Client service
Take a look at our full comparison post here,to learn about the differences between systems in-depth
Best Home Ventilation Systems: HRV vs DVS vs SmartVent
What If My Home Is Both Cold and Damp?
If budget allows, the best solution is to install both a heat pump and a ventilation system.
This is true for every home, regardless of the symptoms you are experiencing.
This combo:
- Heats the air
- Removes moisture
- Creates a truly comfortable and healthy home
If your budget is limited:
- Prioritise the bigger problem (cold vs damp)
- Start with one system and add the other later if possible
Recommendations by Home Type:
- Older Homes: Heat pumps + Positive pressure ventilation
- Modern, Airtight Homes: Ducted heating/cooling OR Mutli-split heat pumps + Forced air ventilation with heat recovery
Do you need a ventilation system if you have a heat pump?
Yes, if the house is damp: The Conduction Company's view is that a heat pump will not fix damp. A heat pump or air conditioner is not the right fix for mould, dampness or condensation, and only a ventilation system deals with them properly. A heat pump recirculates the room air and adds no fresh air. Fresh air is also the only real fix for a musty smell, especially in a home surrounded by tall trees, in a damp area or near the coast.
Is DVS or HRV better?
Neither wins outright, in The Conduction Company's view. HRV and DVS are best known for positive pressure systems that draw filtered air from the roof space and push it into the home to cut condensation. So which is better, HRV or DVS, comes down to your home, your moisture problem and your budget.
For an older Auckland home with condensation, The Conduction Company rates DVS good value: simple, reliable and affordable. Clients who have priced HRV, and staff who fitted it in previous roles, tell The Conduction Company it comes in above DVS. The Conduction Company installs SmartVent, and its staff have installed and repaired HRV and DVS in previous roles. Its HRV vs DVS vs SmartVent comparison, linked above, sets them side by side.
How does HRV work?
HRV is both a brand and the short name for heat recovery ventilation, The Conduction Company explains, and the HRV brand sells both kinds of system. Its best known kind is positive pressure: a unit in the roof space filters warm, dry air from the ceiling void and pushes it into the home, forcing stale, moist air out. A DVS system is best known for the same positive pressure design. A true heat recovery system, also called MVHR or balanced ventilation, works differently: it extracts warm, stale air, pulls the heat out of it, and uses that heat to warm the fresh air coming in.
For their positive pressure systems, the difference between DVS and HRV is mostly the product, not the principle. In summer the roof space gets hot, so a positive pressure system can push that heat into the house. The fix is a summer kit, which swaps the roof-space air for cooler outside air, and The Conduction Company fits one on the SmartVent systems that take it. The Conduction Company installs SmartVent, not the HRV brand.
How much does a DVS system cost in NZ?
The Conduction Company publishes no installed price for DVS, because DVS prices and sells its own systems. A DVS system is a positive pressure system, so the closest like-for-like price is The Conduction Company's own positive pressure range, set out with its other installed prices in its home ventilation system cost guide. For the best home ventilation system in NZ for the price, The Conduction Company's first choice is SmartVent, because in its experience the product quality is consistently higher for the price.
Do HRV systems use much power?
No, not much: in a positive pressure system like HRV or DVS, The Conduction Company finds the fan is the only real power draw. So is HRV expensive to run? Not in The Conduction Company's experience. A drier home is easier to heat, so the heat pump does not have to work as hard, and most of its clients notice only a negligible difference in their power bill after a system goes in.
How much power a DVS system uses is a similar story. DVS publishes no fan wattage, but its unit sits in the same fan class. That is a very different picture from running a heat pump on dry mode, which uses a lot of energy. The same cost guide covers running costs and filters.
Summary
Choosing between a heat pump and a ventilation system comes down to identifying your home’s biggest problem. If it’s cold, get a heat pump. If it’s damp, get a ventilation system.
In an ideal world, you’d install both for a warm, dry and energy-efficient home.
Your comfort, health and electricity bill will thank you.
Frequently asked questions
What is cheaper to run, a DVS or a heat pump on dehumidify?
A DVS-type ventilation system, in The Conduction Company's experience. Its fan is the only real power draw. A heat pump on dry or dehumidify mode works by cooling the air over cold coils, which uses a lot of energy. It also cools the room, which is not ideal in winter.
Are home ventilation systems worth it?
For a damp Auckland home, yes, says The Conduction Company, and that goes for HRV too. A positive pressure system cuts condensation on windows, reduces mould and makes a house easier to heat. It is worth less in a dry, well insulated home that already has good extraction.
What is the 20 degree rule for heat pumps?
There is no settled 20 degree rule for heat pumps in New Zealand, and The Conduction Company does not work to one. It usually just means setting a heat pump to about 20 degrees. The Conduction Company sets a winter living room at 21, because the edges of the room sit nearer 18, as its guide to whether heat pumps are worth it in NZ explains.
Why is my bill so high with a heat pump?
A dirty unit is one cause, but rarely the biggest, The Conduction Company finds. More often the unit is too small for the room and runs flat out for hours, or the house does not hold its heat. Its guide to heat pump servicing in Auckland answers this in full.
What is the downside to heat pumps?
The upfront cost, and for some people the look of a unit on the wall, The Conduction Company finds. The bigger practical risk is a unit too small for the room, which runs flat out and never reaches temperature. And for a damp home, a heat pump adds no fresh air, so it does not fix the damp.
