Introduction
The building sector is a major contributor of carbon emissions. In the United States of America, the building sector accounts for about 39% of the total carbon dioxide output (Griggs, et al., 2013). In essence, sustainable building and green design is a major component of building conferences. The carbon dioxide produced from the building sector has contributed greatly to the increase in the world temperatures and global warming. It has been estimated that this increase in the production of carbon dioxide will increase the global temperatures to an extreme of 10 degree farenhight (Weerasinghe, 2007).  By definition, the carbon footprint refers to the amount of carbon dioxide that is produced when under by each human activity.
Determining the carbon footprint of a building is an important step towards the low carbon strategy. If left unchecked, an increase in the carbon footprint will lead to an increase tin the frequency of floods, tsunamis, droughts and the spread of diseases among other unwanted calamities. Moreover, this reduction in the carbon footprint has numerous benefits but mainly the cost benefits as well as the revenue generated. There are numerous strategies in place that aim to counter the production of the carbon dioxide but the first step is to determine the amount produced.
Software can be used to determine the carbon footprint. In essence, there can be a strategy implementation phase that will aim to reduce the production of this gas. Eventually, there will be a reduction in the running costs of buildings, an increase in the property value and an improvement in the LEED score among other factors. In this analysis, the software to be used are five in number as explained in the following sections.
 
Question 1

  1. The nature conservancy carbon calculator at link https://www.nature.org/en-us/get-involved/how-to-help/consider-your-impact/carbon-calculator/

The organization tries to determine the carbon output in relation to the country, the city, the county and the state. This, in essence, presents a platform for a comparison with the output of the country. Nevertheless, the final goal of the calculator is to ensure that there are strategies in place that enables the user to reduce the carbon footprint. The three strategies are focused on shopping, transportation and housing.
The four categories of classifying the carbon footprint are shopping, travel, food and home. Nevertheless, all this is dependent on the number of occupants as well as the annual income.  Transportation is dependent on the type of fuel use, the number of vehicles and the frequency with which the mean of transportation is used. On the other hand, housing analysis focuses on the electricity, natural, gas, and other fuels that are used annually. The consumption and the shopping depend on the nature, whether average or frequent.
In essence, the results indicate that transportation is a key in the carbon footprint. This has been described as 181% more than the average. Nevertheless, the total carbon footprint is 121 tons of carbon dioxide per year.

  1. The carbon footprint limited calculator obtained from https://www.carbonfootprint.com/calculator.aspx

The organization tries to estimate the carbon footprint aattributed a specified duration of time. In essence, the main emphasis is the cumulative carbon footprint, for either a year, two years. Etc. This will be as per the country and the state.
There are six categories that are used in the calculation: house, flights, car, motorbike, bus & rail and secondary. The household calculation is based on the annual consumption of electricity, gas, heating oil, liquid petroleum gas, coal, propane and wooden pellets. Flights depend on the class travelled, the trips covered and the destination. The car depends on the type of vehicle, the mileage and the efficiency while motorbike calculation is based on the same as vehicle. Nevertheless, the bus and trains reflects ion the frequency as well as the mileage covered while secondary footprint emanates from equipment satisfying other necessities such as television, telephone, books, and magazines among others.
The results indicate the carbon footprint is 1.45 metric tons per year. The output is cumulative of the carbon output from the aforementioned sectors. Nevertheless, there is an option to offset the total amount of carbon dioxide emitted.

  1. Carbon footprint estimation from terrapass derived from the link https://www.terrapass.com/carbon-footprint-calculator

 The organization aims at estimating the carbon footprint from an individual and compares it to the total output of the United States. In essence, it determines the number of trees that should be actually planted in order to reduce the emission. As such, it is focused on educating individuals on the benefits of a green planet.
There are four criteria that are used in estimating the carbon footprint; vehicles, house hold., air transport ,vehicle transport and public transport. To begin with, the electricity, natural gas, propane, heating oil gasoline and diesel are used in estimating the annual household energy consumption. Air travel depends on the class of travel as well as the mileage. The frequency of using public transport as well as the private means is also used in estimating the carbon footprint.
As per the results, the carbon footprint emanating from the vehicle usage is highest. This has been largely influenced by the number of trips made and the mileage. Nevertheless, the total annual carbon footprint is 7,109,704 pounds.

  1. Carbon footprint from cool climate derived from the link http://coolclimate.berkeley.edu/carboncalculator

The main purpose of this organization is to compare the carbon footprint of similar residential areas.  This is dependent on the number of people and the income. However, this is only based in the United States.
The criteria used in the analysis includes the dependence on specific goods and services, the means of transport, and the housing utility use. As with the housing, the calculation is based on the water use, the electricity consumption, the gas, the heating consumption and the natural gas usage. Shopping is dependent on the amounts of commodities and services purchased on an annual basis. Finally, transportation depends on the mileage by each available vehicle and the simplicity of air and public transport.
As from the results, the total carbon footprint is about 45.6 tons of carbon dioxide annually. This is just below 46 tons annual carbon dioxide output which is the estimated carbon dioxide output of similar households. Nevertheless, the highest output is derived from the house consumption. The carbon footprint from the house consumption is 15 tons.

  1. Carbon footprint from US EPA derived from the link https://www3.epa.gov/carbon-footprint-calculator/

This organization has developed the calculator in order to understand the carbon output from   either an individual, a business or an event. In essence, the calculator can be downloaded for offline use. Nevertheless, the focus is on the strategies that can be used in order to reduce the carbon footprint, particularly on the road, at home and the waste.
In trying to establish the carbon footprint, the software focuses on the number of occupants, the primary heating source and the zip code. Nevertheless, the main focus of the software is the number of vehicles, the waste and the energy consumption.  The carbon footprint from the waste depends on the type of materials recycled as well as the frequency of recycling. On the other hand, the house energy depends on the annual consumption of electricity, natural gas, propane, and fuel oils. An important consideration in this is the green energy that is purchased. Finally, the vehicle usage depends on the number, the mileage and the maintenance.
As per the analysis, the carbon footprint of every individual is 11,974,634 pounds per year. This has been compared to the average emissions of individuals of similar households.
 
 
 
Question 2A
The calculator chosen to determine the hypothetical reduction of carbon footprint is the one from US EPA. The calculator presents an option for the reduction of carbon emission on the vehicle usage, the house energy consumption or the waste.’
By reducing the heating requirements of the house, especially in the winter, there is a significant reduction in the carbon emission. When there is a reduction in the housing heating thermostat by 10 degrees, there is a reduction in the carbon emission by about 19%. This is demonstrated from the following screenshot.
Original carbon footprint
 
Improved carbon footprint
Question 2B

  Energy use Emission factor Annual metric tons CO2
gasoline 4800 gallons 8.78 kg CO2 per gallon 22.944 tons CO2
Diesel 180000gallons 10.21 kg CO2 per gallon 183.78 tons CO2
Electricity 10800kWh 527.9 lb MW/hr 2.85
Natural gas/ propane 50000 gallons 0.05 kg CO2 per gallon 2.5

 
Question 3
By using the different calculators, there was no specific conclusion about the carbon footprint of the household. This is majorly influenced by the difference in the criteria used to determine the amount of carbon output. Moreover, there was a difference in the depth of analysis used in each criteria. Some of the calculators were so shallow with a case example the terrapass calculator. Other calculators such as the US EPA calculator were too deep and considered the strategies that may be implemented in order to reduce the carbon output. In other cases, some calculators based their output on factors such as the average house income. This resulted to a disparity in the output of the different software.
In essence, there are some software such as the one from the US EPA that critically examines the carbon emission form different human activities. The calculator has focused both on the house as well as transportation activities that contribute significantly to carbon emission. On top of that, the software considers the waste management practices that may lead to an increase in the amount of carbon dioxide produced by human activities. In these sections, the software provides a platform to analyze the different strategies that can be used in order to reduce the carbon dioxide output. As a matter of fact, each strategy used results to a certain percentage reduction of the total carbon footprint. It is a user friendly feature since it enables an individual to determine the strategies that can contribute significantly to a reduction in his/her final footprint.
References
Butland , B., 2002. Environment,economy and society:fitiing them together into sustainable development. sustainable development.
Griggs, D., Stafford-Smith, M., Gaffney, O. & Rockstrom, J., 2013. Policy:sustainable development goals for people and planet. s.l.:s.n.
Weerasinghe, G. S., 2007. LEED-PDRI framework for pre project planning of sustainable building of projects. Journal of Green Building.