diff --git a/src/app/components/plan/PartDropdown.tsx b/src/app/components/plan/PartDropdown.tsx
index 35e9e32f..1a9ca63c 100644
--- a/src/app/components/plan/PartDropdown.tsx
+++ b/src/app/components/plan/PartDropdown.tsx
@@ -1,16 +1,11 @@
 import { Fragment } from "react";
 import { Menu, Transition } from "@headlessui/react";
 import { ChevronDownIcon } from "@heroicons/react/20/solid";
-
-type Option = {
-  label: string;
-  value: string;
-  cost: number;
-};
+import { PartOption } from "@/types/parts";
 
 type DropdownProps = {
-  options: Option[];
-  onSelectOption: (option: Option) => void;
+  options: PartOption[];
+  onSelectOption: (option: PartOption) => void;
   selectedOption: string;
 };
 
@@ -39,7 +34,7 @@ export default function PartDropdown({
       >
         <Menu.Items className="origin-bottom left-0 w-full rounded-md shadow-lg bg-white ring-1 ring-black ring-opacity-5 focus:outline-none">
           {options.map((option) => (
-            <Menu.Item key={option.value}>
+            <Menu.Item key={option.part}>
               {({ active }) => (
                 <button
                   className={`${
diff --git a/src/app/components/plan/PartModal.tsx b/src/app/components/plan/PartModal.tsx
index a4b99403..f08d7d6a 100644
--- a/src/app/components/plan/PartModal.tsx
+++ b/src/app/components/plan/PartModal.tsx
@@ -2,16 +2,21 @@ import { Dialog, Transition } from "@headlessui/react";
 import { Dispatch, Fragment, SetStateAction, useState } from "react";
 import { TanButton } from "../Buttons";
 import PartDropdown from "./PartDropdown";
+import { formatNumber } from "@/app/utils";
+import type { Part, PartOption } from "@/types/parts";
 
-type ParModalProps = {
+type PartModalProps = {
   title: string;
   isOpen: boolean;
   setIsOpen: Dispatch<SetStateAction<boolean>>;
-  options: { label: string; value: string; cost: number }[];
+  options: PartOption[];
   selectedOption: string;
   setSelectedOption: Dispatch<SetStateAction<string>>;
-  cost: number;
-  setCost: Dispatch<SetStateAction<number>>;
+  parts: Part[];
+  setParts: Dispatch<SetStateAction<Part[]>>;
+  partIndex: number;
+  setTotalCost: Dispatch<SetStateAction<string>>;
+  setWorkHours: Dispatch<SetStateAction<number>>;
 };
 
 export default function PartModal({
@@ -21,18 +26,31 @@ export default function PartModal({
   options,
   selectedOption,
   setSelectedOption,
-  cost,
-  setCost,
-}: ParModalProps) {
+  parts,
+  setParts,
+  partIndex,
+  setTotalCost,
+  setWorkHours,
+}: PartModalProps) {
   function handleModalSubmit() {
     // Right now the dropdown is setting the state on the selected option so we might not need
     setSelectedOption(optionInput);
-    setCost(costInput);
+    // recalculate total cost
+    parts[partIndex].cost = costInput;
+    setTotalCost(formatNumber(parts.reduce((sum, part) => sum + part.cost, 0)));
+
+    // recalculata total hours
+    parts[partIndex].workHours = hoursInput;
+    setWorkHours(parts.reduce((sum, part) => sum + part.workHours, 0));
+    setParts(parts);
     setIsOpen(false);
   }
 
-  const [costInput, setCostInput] = useState<number>(cost);
+  const [costInput, setCostInput] = useState<number>(parts[partIndex].cost);
   const [optionInput, setOptionInput] = useState<string>(selectedOption);
+  const [hoursInput, setHoursInput] = useState<number>(
+    parts[partIndex].workHours
+  );
 
   return (
     <>
@@ -80,10 +98,11 @@ export default function PartModal({
                     <PartDropdown
                       options={options}
                       onSelectOption={(option) => {
-                        setOptionInput(option.value);
+                        setOptionInput(option.part);
                         setCostInput(option.cost);
+                        setHoursInput(option.workHours);
                       }}
-                      selectedOption={selectedOption}
+                      selectedOption={optionInput}
                     />
                   </div>
 
diff --git a/src/app/components/plan/PlanPart.tsx b/src/app/components/plan/PlanPart.tsx
index 9ba72ac9..0ddd726b 100644
--- a/src/app/components/plan/PlanPart.tsx
+++ b/src/app/components/plan/PlanPart.tsx
@@ -1,53 +1,74 @@
-import { useState } from "react";
+import { Dispatch, SetStateAction, useState } from "react";
 import PartModal from "./PartModal";
 import { formatNumber } from "@/app/utils";
+import type { Part, PartOption } from "@/types/parts";
 
 type PlanPartProps = {
+  partIndex: number;
   title: string;
   cost: number;
-  co2Emissions: number;
+  co2Reduction: number;
   workHours: number;
+  parts: Part[];
+  setParts: Dispatch<SetStateAction<Part[]>>;
+  setTotalCost: Dispatch<SetStateAction<string>>;
+  setWorkHours: Dispatch<SetStateAction<number>>;
 };
 
 export default function PlanPart({
+  partIndex,
   title,
   cost,
-  co2Emissions,
+  co2Reduction,
   workHours,
+  parts,
+  setParts,
+  setTotalCost,
+  setWorkHours,
 }: PlanPartProps) {
   const [isOpen, setIsOpen] = useState(false);
-  const [partCost, setPartCost] = useState(cost);
+  const [partCost, setPartCost] = useState(parts[partIndex].cost);
 
   // These are temporary options for the demo
-  const options = [
+  const options: PartOption[] = [
     {
       label: "option 1: £" + formatNumber(cost + 0.05 * cost),
-      value: "option 1",
+      part: "option 1",
       cost: cost + 0.05 * cost,
+      co2Reduction: co2Reduction - 0.05 * co2Reduction,
+      workHours: workHours + 0.05 * workHours,
     },
     {
       label: "option 2: £" + formatNumber(cost + 0.1 * cost),
-      value: "option 2",
+      part: "option 2",
       cost: cost + 0.1 * cost,
+      co2Reduction: co2Reduction - 0.1 * co2Reduction,
+      workHours: workHours + 0.1 * workHours,
     },
     {
       label: "option 3: £" + formatNumber(cost + 0.15 * cost),
-      value: "option 3",
+      part: "option 3",
       cost: cost + 0.15 * cost,
+      co2Reduction: co2Reduction - 0.15 * co2Reduction,
+      workHours: workHours + 0.15 * workHours,
     },
     {
       label: "option 4: £" + formatNumber(cost + 0.2 * cost),
-      value: "option 4",
+      part: "option 4",
       cost: cost + 0.2 * cost,
+      co2Reduction: co2Reduction - 0.2 * co2Reduction,
+      workHours: workHours + 0.2 * workHours,
     },
     {
       label: "option 5: £" + formatNumber(cost + 0.25 * cost),
-      value: "option 5",
+      part: "option 5",
       cost: cost + 0.25 * cost,
+      co2Reduction: co2Reduction - 0.25 * co2Reduction,
+      workHours: workHours + 0.25 * workHours,
     },
   ];
 
-  const [selectedOption, setSelectedOption] = useState(options[0].value);
+  const [selectedOption, setSelectedOption] = useState(options[0].part);
 
   return (
     <div
@@ -59,13 +80,13 @@ export default function PlanPart({
       <h2 className="flex-1 text-lg font-bold mb-2 text-left">{title}</h2>
       <div>{selectedOption}</div>
       <div className="flex-1 text-center">
-        <p>Cost: £{partCost}</p>
+        <p>Cost: £{parts[partIndex].cost}</p>
       </div>
       <div className="flex-1 text-center">
-        <p>CO2 Reduction: {co2Emissions}</p>
+        <p>CO2 Reduction: {parts[partIndex].co2Reduction}</p>
       </div>
       <div className="flex-1 text-center">
-        <p>Work Hours: {workHours}</p>
+        <p>Work Hours: {parts[partIndex].workHours}</p>
       </div>
       <PartModal
         title={title}
@@ -74,8 +95,11 @@ export default function PlanPart({
         options={options}
         selectedOption={selectedOption}
         setSelectedOption={setSelectedOption}
-        cost={partCost}
-        setCost={setPartCost}
+        parts={parts}
+        setParts={setParts}
+        partIndex={partIndex}
+        setTotalCost={setTotalCost}
+        setWorkHours={setWorkHours}
       />
     </div>
   );
diff --git a/src/app/portfolio/[slug]/property/[lmkKey]/plan/page.tsx b/src/app/portfolio/[slug]/property/[lmkKey]/plan/page.tsx
index d4d754ed..5c00e865 100644
--- a/src/app/portfolio/[slug]/property/[lmkKey]/plan/page.tsx
+++ b/src/app/portfolio/[slug]/property/[lmkKey]/plan/page.tsx
@@ -11,6 +11,7 @@ import EditEpctargetModal from "@/app/components/property/EditEpcTargetModal";
 import Link from "next/link";
 import BudgetModal from "@/app/components/plan/BudgetModal";
 import { formatNumber } from "@/app/utils";
+import { Part } from "@/types/parts";
 
 export default function Plan({
   params,
@@ -27,46 +28,110 @@ export default function Plan({
 
   // Temp config for the demo
   const partsConfig = [
-    { part: "Roof", cost: 1200, co2Emissions: 50, workHours: 20 },
-    { part: "Walls", cost: 900, co2Emissions: 50, workHours: 20 },
-    { part: "Floors", cost: 4300, co2Emissions: 50, workHours: 20 },
-    { part: "Window Glazing", cost: 6000, co2Emissions: 50, workHours: 20 },
+    {
+      part: "Roof",
+      option: "option 1",
+      cost: 1200,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Walls",
+      option: "option 1",
+      cost: 900,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Floors",
+      option: "option 1",
+      cost: 4300,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Window Glazing",
+      option: "option 1",
+      cost: 6000,
+      co2Reduction: 50,
+      workHours: 20,
+    },
     {
       part: "Window Draughproofing",
+      option: "option 1",
       cost: 10,
-      co2Emissions: 50,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Door Insulation",
+      option: "option 1",
+      cost: 250,
+      co2Reduction: 50,
       workHours: 20,
     },
-    { part: "Door Insulation", cost: 250, co2Emissions: 50, workHours: 20 },
     {
       part: "Door Draughproofing",
+      option: "option 1",
       cost: 70,
-      co2Emissions: 50,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Heating",
+      option: "option 1",
+      cost: 2300,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Hot Water",
+      option: "option 1",
+      cost: 5290,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Solar Panels",
+      option: "option 1",
+      cost: 1300,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Solar Hot Water",
+      option: "option 1",
+      cost: 1000,
+      co2Reduction: 50,
+      workHours: 20,
+    },
+    {
+      part: "Lighting",
+      option: "option 1",
+      cost: 20,
+      co2Reduction: 50,
       workHours: 20,
     },
-    { part: "Heating", cost: 2300, co2Emissions: 50, workHours: 20 },
-    { part: "Hot Water", cost: 5290, co2Emissions: 50, workHours: 20 },
-    { part: "Solar Panels", cost: 1300, co2Emissions: 50, workHours: 20 },
-    { part: "Solar Hot Water", cost: 1000, co2Emissions: 50, workHours: 20 },
-    { part: "Lighting", cost: 20, co2Emissions: 50, workHours: 20 },
     {
       part: "Chimneys/ Open Fire Places",
+      option: "option 1",
       cost: 350,
-      co2Emissions: 50,
+      co2Reduction: 50,
       workHours: 20,
     },
   ];
 
-  const totalWorkHours = partsConfig.reduce(
-    (sum, part) => sum + part.workHours,
-    0
-  );
-
-  const partsTotalCost = partsConfig.reduce((sum, part) => sum + part.cost, 0);
+  // Manage state of the selected parts - start with partsConfig
+  const [parts, setParts] = useState<Part[]>(partsConfig);
 
   const [budget, setBudget] = useState<number | "Not set">("Not set");
-  const [totalCost, setTotalCost] = useState(partsTotalCost);
-  const [installTime, setInstallTime] = useState(totalWorkHours);
+  const [totalCost, setTotalCost] = useState<string>(
+    formatNumber(parts.reduce((sum, part) => sum + part.cost, 0))
+  );
+  const [workHours, setWorkHours] = useState(
+    parts.reduce((sum, part) => sum + part.workHours, 0)
+  );
+
   const [isEditModalOpen, setIsEditModalOpen] = useState(false);
   const [isBudgetModalOpen, setIsBudgetModalOpen] = useState(false);
   const [targetEpcRating, setTargetEpcRating] = useState<EpcRating | "">(
@@ -92,6 +157,7 @@ export default function Plan({
   }
 
   const propertyData = data.rows.filter((row) => row["lmk-key"] === lmkKey)[0];
+
   return (
     <section>
       <div className="max-w-6xl mx-auto p-6 flex flex-col items-center">
@@ -101,14 +167,19 @@ export default function Plan({
         </div>
         <div className="flex w-full">
           <div className="w-3/4 pr-4">
-            {partsConfig.map((part, index) => {
+            {parts.map((part, index) => {
               return (
                 <PlanPart
                   key={index}
+                  partIndex={index}
                   title={part.part}
                   cost={part.cost}
-                  co2Emissions={part.co2Emissions}
+                  co2Reduction={part.co2Reduction}
                   workHours={part.workHours}
+                  parts={parts}
+                  setParts={setParts}
+                  setTotalCost={setTotalCost}
+                  setWorkHours={setWorkHours}
                 />
               );
             })}
@@ -143,7 +214,7 @@ export default function Plan({
                 </Link>
                 <li className="px-2 mb-2">Total cost: £{totalCost}</li>
                 <li className="px-2 mb-2">
-                  Installation Time: {installTime} hours
+                  Installation Time: {workHours} hours
                 </li>
               </ul>
             </div>