<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>EVa5I7bHFq9mnYK</author><text>I have such system running 24&amp;#x2F;7 for 5 years now in my apartment. It costs $20&amp;#x2F;month in the winter because it needs to heat the freezing air coming in. There is also noticable noise if I am doing physical activity and it needs to blow the CO2 out more quickly.</text><parent_chain><item><author>ahaucnx</author><text>I am living in an area with periodic very high air pollution. So opening the windows to bring CO2 down will bring in fine dust pollution.&lt;p&gt;I retrofitted my house with a demand controlled fresh air ventilation system that takes outside air runs it through a set of high performance filters and pushes it into the house.&lt;p&gt;I can consistently keep PM2.5 levels at zero and CO2 below 600ppm.&lt;p&gt;I wrote an article about it [1] including detailed charts about CO2 build up.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.airgradient.com&amp;#x2F;open-airgradient&amp;#x2F;blog&amp;#x2F;positive-pressure-systems-for-clean-air&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.airgradient.com&amp;#x2F;open-airgradient&amp;#x2F;blog&amp;#x2F;positive-p...&lt;/a&gt;</text></item></parent_chain></comment><story><title>I bought a CO2 monitor and it broke me</title><url>https://www.theatlantic.com/health/archive/2023/02/carbon-dioxide-monitor-indoor-air-pollution-gas-stoves/672923/</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>cactusplant7374</author><text>That is truly awesome. How much did you spend?</text><parent_chain><item><author>ahaucnx</author><text>I am living in an area with periodic very high air pollution. So opening the windows to bring CO2 down will bring in fine dust pollution.&lt;p&gt;I retrofitted my house with a demand controlled fresh air ventilation system that takes outside air runs it through a set of high performance filters and pushes it into the house.&lt;p&gt;I can consistently keep PM2.5 levels at zero and CO2 below 600ppm.&lt;p&gt;I wrote an article about it [1] including detailed charts about CO2 build up.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.airgradient.com&amp;#x2F;open-airgradient&amp;#x2F;blog&amp;#x2F;positive-pressure-systems-for-clean-air&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.airgradient.com&amp;#x2F;open-airgradient&amp;#x2F;blog&amp;#x2F;positive-p...&lt;/a&gt;</text></item></parent_chain></comment><story><title>I bought a CO2 monitor and it broke me</title><url>https://www.theatlantic.com/health/archive/2023/02/carbon-dioxide-monitor-indoor-air-pollution-gas-stoves/672923/</url></story>