Cold and high RH. Buy an extra Heater to solve both issues?

[greenops]

I have a 4x4 grow tent in my bedroom. It's winter now where I live and the room stays at 20C - 21C (69F) and 50 - 60% RH. I have to open the windows to bring the RH down to the 40% range, but it can get cold quick. The lights go on at 7pm til 7am. Even with the lights on, the temperature doesn't go above 22C (71F) and the RH can spike up to 65-70% especially as I'm using a drip to waste system to water. I grow under 550w LED lights. I never had this problem when I grew with HPS.

I already bought an dehumidifier from Amazon which doesn't help. Now I'm wondering if a small heater can effectively decrease the RH? If so, any tips what kind of a heater I should by? I'm not looking to spend a lot.. probably around 100- 150 USD. I really hope this can solve both issues at once.

 

[Switcher56]

Why do you want 40% RH?

 

[greenops]

Why do you want 40% RH?

Based on what's stuck in my mind from years of reading, I thought 40% - 45% RH is what's healthy for flowering.

Thanks for this chart. Can you help me understand it better? As I'm now in the mid-flowering stage, do I have to target a VPD of 1.2-1.6, or the healthy 0.8-1.2?

 

[Creeperpark]

When it is cold in my grow and I'm in veg., I just add more light and heat with extra light. In flowering, the temps you stated above are perfect and not a problem. If the temps drop at the end of the grow, it's always a s good deal because the plant speeds into flowering in fear of Winter. The 50 to 60% RH isn't a problem unless you keep your soil wet all the time. Staying in the 40% is good when you have flowers but not absolutely mandatory. The problem with using heaters in a tent is it's hard to keep the environment steady. A heater can burn up atmospheric conditions in just a few hours. These lights are cheap and do a good job heating a grow.