What’s the ideal temperature and humidity to sleep well in the winter?

A lot of time and effort is put into designing a bedroom, ensuite and walk-in robe but how much planning goes into thinking about the ideal temperature and humidity that’s conducive for a satisfying slumber, especially in the colder months?

Data from the 2018 General Social Survey (GSS) showed that a third of New Zealand homes were too cold in winter, and over a third were too warm in summer. As part of the year-long survey, Stats NZ took temperature measurements in approximately 6,700 homes.

How is sleep affected by temperature?

Effects of heat or cold exposure can increase wakefulness and decrease rapid eye movement sleep. Deep, slow wave sleep is also affected so you often wake up feeling tired throughout the day and crave coffee like mad! Excessively high or low ambient temperature can affect sleep even in healthy humans without insomnia which shows why it’s so important to live in a healthy home built well above the building code.

Temperature linked to thermoregulation in our bodies affects the mechanism regulating sleep and therefore our sleep cycles. Increases in wakefulness are more prevalent in cooler ambient temperatures than with warmer ones so colder rooms appear to impact you more than rooms that are too warm. This demonstrates how important it is to have a well-insulated home, ideally radiant heat is to some extent introduced and maintained in your bedroom from the warm afternoon sun depending on your house plan and site orientation.

Choosing the right amount of bedding to keep you warm (but not so you overheat during the night) is also very important to ensure a good kip.

Are we sensitive to humidity when it comes to sleeping?

We’re all pretty familiar with warm muggy evenings that make us ultra restless but when it’s colder it’s not a walk in the park either – plus your bedroom windows may drip with condensation if it’s over 40% humidity.  An indoor humidity level of 30 – 40% is recommended in the winter months and 30%-50% for the rest of the year however it still comes down to personal preference and is influenced by your overall level of health.

Can humidity changes make you sick?

Bacteria and viruses can really take hold in humid conditions hence why some people benefit by drying the air more in the winter, such as using a moisture extraction system or ducted heat pump in their home.

Spending time in an environment with too much humidity can actually make you ill, especially from respiratory infections. The bacteria and viruses (and dust mites) that can cause illness thrive and grow in air that’s above 60 % relative humidity.

High humidity is detrimental to calm sleeping time. Naturally, too much humidity in the air makes it hard for the body to release its excess moisture (through evaporation), a process that helps stabilise body temperature that is equivocally paramount for sleep. This means a long night full of sweating, turning and tossing, which is not a recommended sleeping state! Sometimes we even welcome a blustery dry Norwester when it arrives in the winter just to reduce overall humidity levels.

What’s a good humidity level for winter sleeping?

Essentially, being in a room that is either too warm, cold draughty or humid is not conducive to sleep. A good heat pump or an oscillating fan can reduce moisture in the air if you don’t have the luxury of a sophisticated moisture control system.

Don’t get us wrong, a little humidity is not bad at all for sleep. Air that is too moisture-deficient may upset your sinuses, dry and irritate your throat or bring on headaches.

How do you monitor room temperature and humidity?

You can buy a plain wall thermometer or a fully-fitted hygrometer. The Sensibo app can be purchased to automate most heat pumps and can tell you both temperature and humidity, you can even set it to maintain both at a certain level throughout the night and day.

Rest easy building with Green Homes

We’re still far from ideal but one New Zealand study done back in in 2010 found we had less than 5% of homes that had healthy temperatures overnight in their bedrooms so we’ve come along way! Optimal Insulation and heating is key to keeping you healthy in winter months which is why you can sleep well with a warm, dry energy efficient home!