Does a Bigger Volume Mean More Heating and Cooling Load?

first_imgWhat happens to the heating and cooling loads when you encapsulate an attic? With the insulation and air barrier at the ceiling below the attic, you’re excluding the attic space. That volume of air up there isn’t involved in the conditioning of the home. But when you move the enclosure to the roofline (usually by installing spray foam insulation beneath the roof deck), now the attic’s volume is included in the conditioned space.Occasionally I hear people say the loads will be higher because of the extra volume. Does having more air inside really increase the loads?A load calculation refresherTo understand this issue, let’s take a look at what goes into doing a load calculation. To do it right, you have to consider all the ways heat enters or leaves a home. Here they are:Enclosure loads – This is where most of the heating and cooling load comes from. It’s the heat that conducts through walls, windows, doors, ceilings, and floors. It’s also the radiant heat that comes (mainly) through the windows, also known as direct solar gain.Infiltration load – The air that leaks in through the building enclosure is really a sub-category of enclosure loads. But it’s worth separating it out, if for no other reason than it’s entered separately in the calculation.Ventilation load – The outdoor air you bring in for ventilation adds heat (both sensible and latent) in summer and results in heat loss in winter.System loads – When you put a heating or cooling system in unconditioned space, there’s heat gain in summer and heat loss in winter at the system. Likewise for the distribution system, whether you use air (ducts) or water (tubing). Duct insulation and sealing and pipe insulation help reduce those gains or losses, but you still have to include what’s left when you’re figuring the total loads.Dehumidification and humidification loads – All dehumidifiers give off heat. Most of them dump that heat into the space you’re dehumidifying. (An exception is the Ultra-Aire SD12,* which is a split-system dehumidifier.) Humidifiers need heat to vaporize the water. Sometimes that heat comes from the heating system itself, in which case it adds to the heating load.Internal loads – People give off heat. Lights give off heat. Appliances give off heat. You get the idea. Those things all get included, too. By entering all the relevant details of the house under consideration, you get the loads for each room, each zone, and the whole house.What’s air got to do with this?So, which one of those loads is related to having a higher volume of air to heat and cool? Well, a couple of them are actually. When air leaks into a house, that unconditioned air has to be heated or cooled. Same with ventilation, except that in this case the “leakage” is intentional.But the question here is about the effect that increasing the volume has on the load. When you encapsulate an attic and bring it into the conditioned space, the additional air in the attic doesn’t add anything to the load. If a sloppy spray foam job resulted in the attic not being airtight, then infiltration into the attic does add to the load, but that’s not what we’re talking about here.Now, you may have more heating and cooling load when you encapsulate an attic, but it’s not because of the extra volume of air inside the conditioned space. When you move the enclosure to the roofline, you also increase the surface area of the home. That can increase the enclosure load. But if you’ve moved your HVAC system from unconditioned to conditioned space, you may end up with a lower load. In hot climates that can be significant.Another factor that increases the loads when you encapsulate an attic is the insulation level. A lot of times, contractors will use a lower R-value for insulation on the roofline than they would on the ceiling below. (Martin Holladay wrote an article about this several years ago here on GBA.)The problem here may be that the people who believe a bigger volume means a bigger load are confusing a correlation with causality. Hey, I get it. All my friends in Maine are trying to reduce their consumption of margarine because it’ll improve their chances of staying married. See the graph below, and you’ll be convinced, too. (See the website Spurious Correlations for more.)Wait, no! That’s a correlation between two variables — but there’s not a shred of evidence that there’s a causal relationship between the two. Same here. We know what factors contribute to heating and cooling loads. The volume of air inside the home is not one of them.* In full disclosure, Therma-Stor, which makes the Ultra-Aire line of dehumidifiers, advertises in the Energy Vanguard Blog. Allison Bailes of Decatur, Georgia, is a speaker, writer, building science consultant, and the author of the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard. RELATED ARTICLESDoes Open-Cell Spray Foam Really Rot Roofs?Saving Energy With Manual J and Manual DHow to Perform a Heat-Loss Calculation — Part 1How to Perform a Heat-Loss Calculation — Part 2Calculating Cooling LoadsIt’s OK to Skimp On Insulation, Icynene Sayslast_img read more

Your Prospects Don’t Need More Time

first_img Essential Reading! Get my 2nd book: The Lost Art of Closing “In The Lost Art of Closing, Anthony proves that the final commitment can actually be one of the easiest parts of the sales process—if you’ve set it up properly with other commitments that have to happen long before the close. The key is to lead customers through a series of necessary steps designed to prevent a purchase stall.” Buy Now “We need time to think it over. We’ll get back to you in a couple of weeks.”This objection has nothing to do with time. It’s something deeper and more important. Your prospects might need a lot of things, but time isn’t one of them. Time doesn’t do anything except relentlessly tick away. And often it takes your opportunity and the change your prospect needs with it.What your prospects need is help. Specifically from a professional.Help UnderstandingYour prospects often need help understanding. They need help understanding how to evaluate your offering. They also need help understanding the trade-offs that they may have to make to get the results they want. They need help evaluating the risks and rewards that will result from their choices.If you aren’t there to help your prospect get a better understanding of how they should evaluate their next move, they’re making that decision without the insight and experience that you can give them.Help Justifying the InvestmentSome of your prospects are willing to pay more for the right solution. But they need help justifying the additional expense. Even though they understand your value proposition, they need to defend the extra expense to their peers, their leadership team, and to their financial overseers.Without your help building the case for a greater investment, the contacts within your dream client company can struggle to get the internal “yes” that both of you need.Help Building ConsensusSometimes a request for more time is an indication that your prospective client needs their team to agree with the decision to buy from you to move forward with your solution. The problem is that if none of those stakeholders know you, or if you mistakenly ignored them throughout the process, it’s difficult for these stakeholders to feel warm and fuzzy about giving a “yes” to a person who didn’t have the courtesy to even meet with them.You can provide immeasurable help in the consensus-building process.If you give your prospective clients more time, you aren’t giving them what they really need. To give them what they really need, you must have the courage to ask for the commitment to help them through the process of change.last_img read more

Seven coaches of Shaktipunj Express derail in Uttar Pradesh

first_imgSeven coaches of the Jabalpur-bound Shaktipunj Express derailed on Thursday in Sonbhadra district of Uttar Pradesh, a railway official said.“The accident occurred at around 6:25 am  and we have already cleared out the site,” railway ministry spokesperson Anil Saxena said.“All passengers were put on the remaining coaches and by 7:28 AM all of them had left the spot. All of them are safe and no one was injured in the accident,” he said.The train was running at a speed of about 40 km/hr which, officials say, prevented any injuries when the incident occurred.This is the third such derailment in the State in less than a month.On August 19, the Utkal Express had derailed in Muzaffarnagar district, killing 22 people and injuring 156.About 100 passengers were wounded when 10 coaches of Kaifiyat Express train derailed after crashing into a dumper which strayed on to the tracks in Auraiya district on August 23.last_img read more

Rahul attacks Modi on farmers’ plight

first_imgTaking forward his ‘question-a-day’ campaign, Congress vice-president Rahul Gandhi on December 7 targeted Prime Minister Narendra Modi over the problems afflicting the farm sector and farmers.Asking his 9th question in the series, he asked, “Neither loan waiver, nor remunerative price for produce, neither received crop insurance benefit, nor were tubewells installed.”The Congress leader also used the ‘Gabbar’ jibe to target the Prime Minister. “Agriculture hit by Gabbar Singh, land snatched and the (Annadatta) farmer was rendered useless. PM sahib, explain why such step-motherly treatment with the farm labour?” he said on Twitter.Mr. Gandhi had earlier termed the Goods and Services Tax as Gabbar Singh Tax to attack the government.Under the ongoing offensive, the Congress leader is using the tagline 22 saal ka hisab, Gujarat maange jawab (22 years of account, Gujarat demands answers), in the run-up to Gujarat elections starting December 9.The Congress vice-president has been tweeting to pose daily questions to the Prime Minister over the performance of the BJP in Gujarat and its “unkept” promises over the past 22 years of its rule in the State.last_img read more