By EA Paint & Light Carpentry7 min read
At a glance
- Dry to touchAverage
- About an hour; recoat in a few hours
- Full cureAverage
- Days to a few weeks
- Nursery
- Finish a few weeks ahead
- Zero VOC means
- Very low, not none; tint can add some
Times are rough averages for planning only. Every house is different — size, condition, repairs and weather all change it. Your written estimate gives the actual schedule for your job.
What is the difference between low VOC and zero VOC paint?
Both refer to the volatile organic compounds in the paint as sold. Low VOC means below a regulatory or industry limit; zero VOC means below a much lower threshold, not literally none. Adding tint can raise either figure. For the real number, check the product data sheet, and look for third-party certifications that test emissions.
What VOCs are, and where they come from in paint
Volatile organic compounds are carbon-based chemicals that evaporate at room temperature. In paint they come mainly from solvents and from additives that help the paint flow, level, resist freezing and form a film as it dries. As the paint dries, they evaporate into the room.
Most of that release happens in the first hours and days, and it tapers off after that. Oil-based and solvent-based paints, primers and finishes have traditionally been the highest in VOCs. Water-based latex and acrylic paints are generally much lower, and over the past few decades both regulations and the market have pushed interior wall paints lower still. Federal rules set maximum VOC content for different categories of paints and coatings, some states and regional air-quality programs set stricter limits, and the product data sheet lists the VOC content of the paint itself.
Low VOC vs zero VOC: the difference
VOC content is usually stated in grams per litre on the product data sheet. The terms on the front of the can are marketing categories that sit on top of that number, and they are not all defined the same way.
No claim
- What it usually means
- Meets the legal limit for its product type
- Watch for
- Oil-based primers and enamels can be much higher than wall paint
Low VOC
- What it usually means
- Below a limit set by a regulation or industry standard
- Watch for
- Which limit — the claim does not say on its own
Zero VOC
- What it usually means
- Below a very low threshold, not literally zero
- Watch for
- Tint can add VOCs unless the colorants are zero-VOC too
Third-party certified
- What it usually means
- Tested by an outside program, often for emissions into the room
- Watch for
- Check what was tested and whether the certification is current
Tip: The VOC figure on a data sheet is often for the untinted base. If it matters to you, ask whether the colorant system used at the store is also low or zero VOC.
Primers, trim enamels and other products
Wall paint is usually the lowest-VOC product in an interior job. The others are where the smell and the numbers tend to be higher, so they are worth asking about by name.
Oil-based primers are still widely used to block water stains and smoke, and to seal torn drywall paper, because they work. They are also among the highest-VOC and strongest-smelling products on the truck. Shellac-based primers have a sharp alcohol smell that fades relatively quickly. Water-based stain-blocking primers exist and suit many situations, though not every one. Trim enamels and cabinet coatings vary widely, from waterborne products with low VOC content to solvent-based ones.
Often the practical answer is to use the stronger product only where it is really needed — a spot-primed stain rather than a whole ceiling — and the low-VOC product everywhere else.
Smell is not the same as VOCs
People judge paint by its smell, and it is a poor guide. Some compounds smell strongly at tiny concentrations, while others can be present without much smell at all. A paint sold as low-odor may be low in VOCs, or it may simply be formulated to smell less.
Content and emissions are also different things. The VOC number on the can is what is in the paint. Some third-party certifications measure what actually comes off the dried wall into the air over a period of days, which is closer to what you breathe. If that matters to you — in a bedroom, say, or for someone sensitive to smells — those certifications and the product data sheet tell you more than the front label.
Drying time vs curing time
Latex wall paint is usually dry to the touch within an hour or so and ready for a second coat within a few hours, depending on the product, the temperature and the humidity. That is drying: the water has left.
Curing is the paint film hardening to its full strength, and it takes much longer — often days to a few weeks. Until then, the paint is easier to scuff and mark, furniture pushed against it can stick, and washing should be gentle. Each manufacturer lists the times on the data sheet, and cold, damp rooms stretch them.
Hang pictures and push furniture back against the walls after the paint is fully dry, and wait longer for doors, trim and shelves, where pieces press against the paint and can stick. Low VOC does not mean faster curing; the two are separate properties.
Painting bedrooms and nurseries
For a room someone sleeps in, choose a zero or low VOC paint with a third-party emissions certification, paint it as far ahead of when it will be used as you can, and ventilate it well while it dries. For a nursery, finishing the painting a few weeks before the baby arrives gives the paint time to cure and the room time to air out. In a house with several bedrooms, painting them on different days means nobody has to sleep in a room painted that afternoon.
If someone in the household is pregnant, has asthma or is sensitive to smells, it is sensible for them to be elsewhere while the room is painted and to ask their doctor about anything specific. And in a house built before 1978, sanding or scraping old painted trim and windows in a nursery is a lead question before it is a VOC question — the old paint matters more than the new.
Ventilating in a Massachusetts winter
Winter is the natural time for interior painting here, but it is also when every window is shut and the heating system is recirculating the same air. A few practical habits help:
- Keep the heat at a normal living temperature. Most paints list a minimum application temperature on the label, often around 50°F, and cold rooms dry slowly.
- Run bathroom and kitchen exhaust fans while painting and for some hours afterward to pull air out of the house.
- Crack a window in the room being painted for short periods, or put a box fan in a window blowing out, if the weather allows.
- Close the door to the painted room and keep people and pets out of it until the smell has faded.
- Keep cans closed when they are not in use, and take empty cans, used rollers and rags out of the living space at the end of each day.
- Change or check the furnace filter after a big interior job, especially if there was sanding.
What to ask your painter about VOCs
If low emissions matter to you, say so before the estimate, not on painting day. Ask which products will be used on walls, ceilings and trim — trim enamels and primers can be higher in VOCs than wall paint — and whether a lower-VOC alternative exists for each. Ask for the product names so you can read the data sheets yourself, and agree on which rooms get painted first, so bedrooms have the longest time to air out before night.
Talk to a local crew
EA Paint & Light Carpentry is a painting and light carpentry company based in Northborough, MA. If you would like the house looked at, call (508) 466-5846 or request a free written estimate. Related services: Interior Painting, Cabinet Painting & Refinishing.
